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 Exercise 5.2

Differentiate the functions with respect to x in Exercises 1 to 8.

1. sin (x2+5)

Solun:- Let y = sin (x2+5)

Let t = x2+5

⇒ y = sin t

Differentiate w.r.t. x:-

<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>We</mi><mo>&#xA0;</mo><mi>know</mi><mo>&#xA0;</mo><mi>that</mi><mo>&#xA0;</mo><mfrac><mrow><mi mathvariant="normal">d</mi><mfenced><mrow><mi>sin</mi><mo>&#xA0;</mo><mi mathvariant="normal">x</mi></mrow></mfenced></mrow><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><mi>cos</mi><mo>&#xA0;</mo><mi mathvariant="normal">x</mi><mspace linebreak="newline"/><mo>&#x21D2;</mo><mo>&#xA0;</mo><mfrac><mi>dy</mi><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><mi>cos</mi><mo>&#xA0;</mo><mi mathvariant="normal">t</mi><mfrac><mi>dt</mi><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mfenced><mn>1</mn></mfenced></math>

t = x2+5

Differentiate w.r.t. x:-

<math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mo>&#x21D2;</mo><mo>&#xA0;</mo><mfrac><mi>dt</mi><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo></mrow><mn>2</mn><mi mathvariant="normal">x</mi><mo>+</mo><mn>0</mn><mo>=</mo><mn>2</mn><mi mathvariant="normal">x</mi><mspace linebreak="newline"/><mi>From</mi><mo>&#xA0;</mo><mi>Eq</mi><mo>.</mo><mo>&#xA0;</mo><mn>1</mn><mo>:</mo><mo>-</mo><mspace linebreak="newline"/><mo>&#x21D2;</mo><mo>&#xA0;</mo><mfrac><mi>dy</mi><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><mi>cos</mi><mfenced><mrow><msup><mi mathvariant="normal">x</mi><mn>2</mn></msup><mo>+</mo><mn>5</mn></mrow></mfenced><mo>&#xD7;</mo><mn>2</mn><mi mathvariant="normal">x</mi><mspace linebreak="newline"/><mo>&#x21D2;</mo><mo>&#xA0;</mo><mfrac><mi>dy</mi><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><mn>2</mn><mi mathvariant="normal">x</mi><mo>.</mo><mi>cos</mi><mfenced><mrow><msup><mi mathvariant="normal">x</mi><mn>2</mn></msup><mo>+</mo><mn>5</mn></mrow></mfenced></math>

2. cos (sin x)

Solun:- Let y = cos (sin x)

Let t = sin x

⇒ y = cos t

Differentiate w.r.t. x:-

<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>We</mi><mo>&#xA0;</mo><mi>know</mi><mo>&#xA0;</mo><mi>that</mi><mo>&#xA0;</mo><mfrac><mrow><mi mathvariant="normal">d</mi><mfenced><mrow><mi>cos</mi><mo>&#xA0;</mo><mi mathvariant="normal">x</mi></mrow></mfenced></mrow><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><mo>-</mo><mi>sin</mi><mo>&#xA0;</mo><mi mathvariant="normal">x</mi><mspace linebreak="newline"/><mo>&#x21D2;</mo><mo>&#xA0;</mo><mfrac><mi>dy</mi><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><mo>-</mo><mi>sin</mi><mo>&#xA0;</mo><mi mathvariant="normal">t</mi><mfrac><mi>dt</mi><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mfenced><mn>1</mn></mfenced></math>

t = sin x

Differentiate w.r.t. x:-

<math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mo>&#x21D2;</mo><mo>&#xA0;</mo><mfrac><mi>dt</mi><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo></mrow><mi>cos</mi><mo>&#xA0;</mo><mi mathvariant="normal">x</mi><mspace linebreak="newline"/><mi>From</mi><mo>&#xA0;</mo><mi>Eq</mi><mo>.</mo><mo>&#xA0;</mo><mn>1</mn><mo>:</mo><mo>-</mo><mspace linebreak="newline"/><mo>&#x21D2;</mo><mo>&#xA0;</mo><mfrac><mi>dy</mi><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><mo>-</mo><mi>sin</mi><mo>&#xA0;</mo><mfenced><mrow><mi>sin</mi><mo>&#xA0;</mo><mi mathvariant="normal">x</mi></mrow></mfenced><mo>&#xD7;</mo><mi>cos</mi><mo>&#xA0;</mo><mi mathvariant="normal">x</mi><mspace linebreak="newline"/></math>

3. sin (ax+b)

Solun:- Let y = sin (ax+b)

Let t = ax+b

⇒ y = sin t

Differentiate w.r.t. x:-

<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>We</mi><mo>&#xA0;</mo><mi>know</mi><mo>&#xA0;</mo><mi>that</mi><mo>&#xA0;</mo><mfrac><mrow><mi mathvariant="normal">d</mi><mfenced><mrow><mi>sin</mi><mo>&#xA0;</mo><mi mathvariant="normal">x</mi></mrow></mfenced></mrow><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><mi>cos</mi><mo>&#xA0;</mo><mi mathvariant="normal">x</mi><mspace linebreak="newline"/><mo>&#x21D2;</mo><mo>&#xA0;</mo><mfrac><mi>dy</mi><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><mi>cos</mi><mo>&#xA0;</mo><mi mathvariant="normal">t</mi><mfrac><mi>dt</mi><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mfenced><mn>1</mn></mfenced></math>

t = ax+b

Differentiate w.r.t. x:-

<math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mo>&#x21D2;</mo><mo>&#xA0;</mo><mfrac><mi>dt</mi><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo></mrow><mi mathvariant="normal">a</mi><mo>+</mo><mn>0</mn><mo>=</mo><mi mathvariant="normal">a</mi><mspace linebreak="newline"/><mi>From</mi><mo>&#xA0;</mo><mi>Eq</mi><mo>.</mo><mo>&#xA0;</mo><mn>1</mn><mo>:</mo><mo>-</mo><mspace linebreak="newline"/><mo>&#x21D2;</mo><mo>&#xA0;</mo><mfrac><mi>dy</mi><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><mi>cos</mi><mo>&#xA0;</mo><mfenced><mrow><mi>ax</mi><mo>+</mo><mi mathvariant="normal">b</mi></mrow></mfenced><mo>&#xD7;</mo><mi mathvariant="normal">a</mi><mspace linebreak="newline"/><mo>&#x21D2;</mo><mo>&#xA0;</mo><mfrac><mi>dy</mi><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><mi mathvariant="normal">a</mi><mo>.</mo><mi>cos</mi><mfenced><mrow><mi>ax</mi><mo>+</mo><mi mathvariant="normal">b</mi></mrow></mfenced></math>

4. sec (tan√x)

Solun:- Let y = sec (tan√x)

Let t = tan√x

⇒ y = sec t

Differentiate w.r.t. x:-

<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>We</mi><mo>&#xA0;</mo><mi>know</mi><mo>&#xA0;</mo><mi>that</mi><mo>&#xA0;</mo><mfrac><mrow><mi mathvariant="normal">d</mi><mfenced><mrow><mi>sec</mi><mo>&#xA0;</mo><mi mathvariant="normal">x</mi></mrow></mfenced></mrow><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><mi>sec</mi><mo>&#xA0;</mo><mi mathvariant="normal">x</mi><mo>.</mo><mi>tan</mi><mo>&#xA0;</mo><mi mathvariant="normal">x</mi><mspace linebreak="newline"/><mo>&#x21D2;</mo><mo>&#xA0;</mo><mfrac><mi>dy</mi><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><mi>sec</mi><mo>&#xA0;</mo><mi mathvariant="normal">t</mi><mo>.</mo><mi>tan</mi><mo>&#xA0;</mo><mi mathvariant="normal">t</mi><mfrac><mi>dt</mi><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mfenced><mn>1</mn></mfenced></math>

t = tan√x

Differentiate w.r.t. x:-

<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>We</mi><mo>&#xA0;</mo><mi>know</mi><mo>&#xA0;</mo><mi>that</mi><mo>&#xA0;</mo><mfrac><mrow><mi mathvariant="normal">d</mi><mfenced><mrow><mi>tan</mi><mo>&#xA0;</mo><mi mathvariant="normal">x</mi></mrow></mfenced></mrow><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><msup><mi>sec</mi><mn>2</mn></msup><mi mathvariant="normal">x</mi><mspace linebreak="newline"/><mrow><mo>&#x21D2;</mo><mo>&#xA0;</mo><mfrac><mi>dt</mi><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo></mrow><msup><mi>sec</mi><mn>2</mn></msup><mfenced><msqrt><mi mathvariant="normal">x</mi></msqrt></mfenced><mo>&#xD7;</mo><mfrac><mn>1</mn><mrow><mn>2</mn><msqrt><mi mathvariant="normal">x</mi></msqrt></mrow></mfrac><mspace linebreak="newline"/><mi>From</mi><mo>&#xA0;</mo><mi>Eq</mi><mo>.</mo><mo>&#xA0;</mo><mn>1</mn><mo>:</mo><mo>-</mo><mspace linebreak="newline"/><mo>&#x21D2;</mo><mo>&#xA0;</mo><mfrac><mi>dy</mi><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><mfrac><mrow><mi>sec</mi><mfenced><mrow><mi>tan</mi><mo>&#xA0;</mo><msqrt><mi mathvariant="normal">x</mi></msqrt></mrow></mfenced><mo>&#xD7;</mo><mi>tan</mi><mfenced><mrow><mi>tan</mi><mo>&#xA0;</mo><msqrt><mi mathvariant="normal">x</mi></msqrt></mrow></mfenced><mo>&#xD7;</mo><msup><mi>sec</mi><mn>2</mn></msup><mfenced><msqrt><mi mathvariant="normal">x</mi></msqrt></mfenced></mrow><mrow><mn>2</mn><msqrt><mi mathvariant="normal">x</mi></msqrt></mrow></mfrac></math>

<math xmlns="http://www.w3.org/1998/Math/MathML"><mn mathvariant="bold">5</mn><mo mathvariant="bold">.</mo><mo mathvariant="bold">&#xA0;</mo><mfrac><mrow><mi mathvariant="bold">sin</mi><mo mathvariant="bold">&#xA0;</mo><mstyle mathvariant="bold"><mrow><mo>(</mo><mi>ax</mi><mo>+</mo><mi>b</mi><mo>)</mo></mrow></mstyle></mrow><mrow><mi mathvariant="bold">cos</mi><mo mathvariant="bold">&#xA0;</mo><mstyle mathvariant="bold"><mrow><mo>(</mo><mi>cx</mi><mo>+</mo><mi>d</mi><mo>)</mo></mrow></mstyle></mrow></mfrac></math>

<math xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="bold">Solun</mi><mo mathvariant="bold">:</mo><mo mathvariant="bold">-</mo><mo mathvariant="bold">&#xA0;</mo><mi>Let</mi><mo>&#xA0;</mo><mi mathvariant="normal">y</mi><mo>=</mo><mfrac><mrow><mi>sin</mi><mo>&#xA0;</mo><mfenced><mrow><mi>ax</mi><mo>+</mo><mi mathvariant="normal">b</mi></mrow></mfenced></mrow><mrow><mi>cos</mi><mo>&#xA0;</mo><mfenced><mrow><mi>cx</mi><mo>+</mo><mi mathvariant="normal">d</mi></mrow></mfenced></mrow></mfrac></math>

Let u = sin (ax+b)  and  v = cos (cx+d)

Differentiate w.r.t. x:-

<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>We</mi><mo>&#xA0;</mo><mi>know</mi><mo>&#xA0;</mo><mi>that</mi><mo>&#xA0;</mo><mfrac><mi mathvariant="normal">d</mi><mi>dx</mi></mfrac><mfenced><mfrac><mi mathvariant="normal">u</mi><mi mathvariant="normal">v</mi></mfrac></mfenced><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><mfrac><mrow><mi>vu</mi><mo>'</mo><mo>-</mo><mi>uv</mi><mo>'</mo></mrow><msup><mi mathvariant="normal">v</mi><mn>2</mn></msup></mfrac></math>

<math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mo>&#x21D2;</mo><mo>&#xA0;</mo><mfrac><mi>dy</mi><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo></mrow><mfrac><mrow><mi>cos</mi><mfenced><mrow><mi>cx</mi><mo>+</mo><mi mathvariant="normal">d</mi></mrow></mfenced><mo>.</mo><mi>cos</mi><mfenced><mrow><mi>ax</mi><mo>+</mo><mi mathvariant="normal">b</mi></mrow></mfenced><mo>.</mo><mi mathvariant="normal">a</mi><mo>-</mo><mi>sin</mi><mfenced><mrow><mi>ax</mi><mo>+</mo><mi mathvariant="normal">b</mi></mrow></mfenced><mo>.</mo><mfenced><mrow><mo>-</mo><mi>sin</mi><mfenced><mrow><mi>cx</mi><mo>+</mo><mi mathvariant="normal">d</mi></mrow></mfenced></mrow></mfenced><mo>.</mo><mi mathvariant="normal">c</mi></mrow><mrow><msup><mi>cos</mi><mn>2</mn></msup><mfenced><mrow><mi>cx</mi><mo>+</mo><mi mathvariant="normal">d</mi></mrow></mfenced></mrow></mfrac><mspace linebreak="newline"/><mrow><mo>&#x21D2;</mo><mo>&#xA0;</mo><mfrac><mi>dy</mi><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo></mrow><mfrac><mrow><mi>cos</mi><mfenced><mrow><mi>cx</mi><mo>+</mo><mi mathvariant="normal">d</mi></mrow></mfenced><mo>.</mo><mi>cos</mi><mfenced><mrow><mi>ax</mi><mo>+</mo><mi mathvariant="normal">b</mi></mrow></mfenced><mo>.</mo><mi mathvariant="normal">a</mi></mrow><mrow><msup><mi>cos</mi><mn>2</mn></msup><mfenced><mrow><mi>cx</mi><mo>+</mo><mi mathvariant="normal">d</mi></mrow></mfenced></mrow></mfrac><mo>+</mo><mfrac><mrow><mi>sin</mi><mfenced><mrow><mi>ax</mi><mo>+</mo><mi mathvariant="normal">b</mi></mrow></mfenced><mo>.</mo><mi>sin</mi><mfenced><mrow><mi>cx</mi><mo>+</mo><mi mathvariant="normal">d</mi></mrow></mfenced><mo>.</mo><mi mathvariant="normal">c</mi></mrow><mrow><msup><mi>cos</mi><mn>2</mn></msup><mfenced><mrow><mi>cx</mi><mo>+</mo><mi mathvariant="normal">d</mi></mrow></mfenced></mrow></mfrac><mspace linebreak="newline"/><mo>&#x21D2;</mo><mo>&#xA0;</mo><mfrac><mi>dy</mi><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><mi mathvariant="normal">a</mi><mo>.</mo><mi>sec</mi><mfenced><mrow><mi>cx</mi><mo>+</mo><mi mathvariant="normal">d</mi></mrow></mfenced><mi>cos</mi><mfenced><mrow><mi>ax</mi><mo>+</mo><mi mathvariant="normal">b</mi></mrow></mfenced><mo>+</mo><mi mathvariant="normal">c</mi><mo>.</mo><mi>sin</mi><mfenced><mrow><mi>ax</mi><mo>+</mo><mi mathvariant="normal">b</mi></mrow></mfenced><mi>tan</mi><mfenced><mrow><mi>cx</mi><mo>+</mo><mi mathvariant="normal">d</mi></mrow></mfenced><mi>sec</mi><mfenced><mrow><mi>cx</mi><mo>+</mo><mi mathvariant="normal">d</mi></mrow></mfenced></math>

6. cos x3 . sin2 (x5)

Solun:- Let y = cos x3 . sin2 (x5)

Let u = cos x3  and  v = sin2 (x5)

Differentiate w.r.t. x:-

<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>We</mi><mo>&#xA0;</mo><mi>know</mi><mo>&#xA0;</mo><mi>that</mi><mo>&#xA0;</mo><mfrac><mi mathvariant="normal">d</mi><mi>dx</mi></mfrac><mfenced><mrow><mi mathvariant="normal">u</mi><mo>.</mo><mi mathvariant="normal">v</mi></mrow></mfenced><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><mi mathvariant="normal">u</mi><mfrac><mi>dv</mi><mi>dx</mi></mfrac><mo>+</mo><mi mathvariant="normal">v</mi><mfrac><mi>du</mi><mi>dx</mi></mfrac></math>

<math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mo>&#x21D2;</mo><mo>&#xA0;</mo><mfrac><mi>du</mi><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo></mrow><mo>-</mo><mi>sin</mi><mo>&#xA0;</mo><mfenced><msup><mi mathvariant="normal">x</mi><mn>3</mn></msup></mfenced><mo>.</mo><mn>3</mn><msup><mi mathvariant="normal">x</mi><mn>2</mn></msup><mspace linebreak="newline"/><mrow><mo>&#x21D2;</mo><mo>&#xA0;</mo><mfrac><mi>du</mi><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo></mrow><mo>-</mo><mn>3</mn><msup><mi mathvariant="normal">x</mi><mn>2</mn></msup><mo>.</mo><mi>sin</mi><mo>&#xA0;</mo><mfenced><msup><mi mathvariant="normal">x</mi><mn>3</mn></msup></mfenced><mspace linebreak="newline"/><mo>&#x21D2;</mo><mo>&#xA0;</mo><mfrac><mi>dv</mi><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><mn>2</mn><mi>sin</mi><mfenced><msup><mi>x</mi><mn>5</mn></msup></mfenced><mo>.</mo><mi>cos</mi><mfenced><msup><mi mathvariant="normal">x</mi><mn>5</mn></msup></mfenced><mo>.</mo><mn>5</mn><msup><mi mathvariant="normal">x</mi><mn>4</mn></msup><mspace linebreak="newline"/><mo>&#x21D2;</mo><mo>&#xA0;</mo><mfrac><mi>dv</mi><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><mn>10</mn><msup><mi mathvariant="normal">x</mi><mn>4</mn></msup><mo>.</mo><mi>sin</mi><mfenced><msup><mi mathvariant="normal">x</mi><mn>5</mn></msup></mfenced><mo>.</mo><mi>cos</mi><mfenced><msup><mi mathvariant="normal">x</mi><mn>5</mn></msup></mfenced><mspace linebreak="newline"/><mo>&#x21D2;</mo><mo>&#xA0;</mo><mfrac><mrow><mi mathvariant="normal">d</mi><mfenced><mrow><mi mathvariant="normal">u</mi><mo>.</mo><mi mathvariant="normal">v</mi></mrow></mfenced></mrow><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mn>10</mn><msup><mi mathvariant="normal">x</mi><mn>4</mn></msup><mo>.</mo><mi>sin</mi><mfenced><msup><mi mathvariant="normal">x</mi><mn>5</mn></msup></mfenced><mo>.</mo><mi>cos</mi><mfenced><msup><mi mathvariant="normal">x</mi><mn>5</mn></msup></mfenced><mo>.</mo><mi>cos</mi><mfenced><msup><mi mathvariant="normal">x</mi><mn>3</mn></msup></mfenced><mo>-</mo><mn>3</mn><msup><mi mathvariant="normal">x</mi><mn>2</mn></msup><msup><mi>sin</mi><mn>2</mn></msup><mfenced><msup><mi mathvariant="normal">x</mi><mn>5</mn></msup></mfenced><mo>.</mo><mi>sin</mi><mo>&#xA0;</mo><mfenced><msup><mi mathvariant="normal">x</mi><mn>3</mn></msup></mfenced><mspace linebreak="newline"/><mo>&#x21D2;</mo><mo>&#xA0;</mo><mfrac><mrow><mi mathvariant="normal">d</mi><mfenced><mrow><mi mathvariant="normal">u</mi><mo>.</mo><mi mathvariant="normal">v</mi></mrow></mfenced></mrow><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mn>10</mn><msup><mi mathvariant="normal">x</mi><mn>4</mn></msup><mi>sin</mi><mfenced><msup><mi mathvariant="normal">x</mi><mn>5</mn></msup></mfenced><mi>cos</mi><mfenced><msup><mi mathvariant="normal">x</mi><mn>5</mn></msup></mfenced><mi>cos</mi><mfenced><msup><mi mathvariant="normal">x</mi><mn>3</mn></msup></mfenced><mo>-</mo><mn>3</mn><msup><mi mathvariant="normal">x</mi><mn>2</mn></msup><msup><mi>sin</mi><mn>2</mn></msup><mfenced><msup><mi mathvariant="normal">x</mi><mn>5</mn></msup></mfenced><mi>sin</mi><mo>&#xA0;</mo><mfenced><msup><mi mathvariant="normal">x</mi><mn>3</mn></msup></mfenced><mo>&#xA0;</mo></math>

7. 2√cot(x2)

Solun:- Let y = 2√cot(x2)

Differentiate w.r.t. x:-

Applying Chain Rule:-

<math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mo>&#x21D2;</mo><mo>&#xA0;</mo><mfrac><mi>dy</mi><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo></mrow><mfrac><mrow><mo>-</mo><mn>2</mn></mrow><mrow><mn>2</mn><msqrt><mi>cot</mi><mfenced><msup><mi mathvariant="normal">x</mi><mn>2</mn></msup></mfenced></msqrt></mrow></mfrac><msup><mi>cosec</mi><mn>2</mn></msup><mfenced><msup><mi mathvariant="normal">x</mi><mn>2</mn></msup></mfenced><mo>.</mo><mn>2</mn><mi mathvariant="normal">x</mi><mspace linebreak="newline"/><mrow><mo>&#x21D2;</mo><mo>&#xA0;</mo><mfrac><mi>dy</mi><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo></mrow><mfrac><mrow><mo>-</mo><mn>2</mn><mi mathvariant="normal">x</mi><mo>.</mo><msup><mi>cosec</mi><mn>2</mn></msup><mfenced><msup><mi mathvariant="normal">x</mi><mn>2</mn></msup></mfenced></mrow><msqrt><mi>cot</mi><mfenced><msup><mi mathvariant="normal">x</mi><mn>2</mn></msup></mfenced></msqrt></mfrac><mspace linebreak="newline"/></math>

8. cos(√x)

Solun:- Let y = cos(√x)

Differentiate w.r.t. x:-

Applying Chain Rule:-

<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>We</mi><mo>&#xA0;</mo><mi>know</mi><mo>&#xA0;</mo><mi>that</mi><mo>&#xA0;</mo><mfrac><mrow><mi mathvariant="normal">d</mi><mfenced><mrow><mi>cos</mi><mo>&#xA0;</mo><mi mathvariant="normal">x</mi></mrow></mfenced></mrow><mi>dx</mi></mfrac><mo>=</mo><mo>-</mo><mi>sin</mi><mo>&#xA0;</mo><mi mathvariant="normal">x</mi><mspace linebreak="newline"/><mrow><mo>&#x21D2;</mo><mo>&#xA0;</mo><mfrac><mi>dy</mi><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>-</mo><mfrac><mn>1</mn><mrow><mn>2</mn><msqrt><mi mathvariant="normal">x</mi></msqrt></mrow></mfrac><mi>sin</mi><mfenced><msqrt><mi mathvariant="normal">x</mi></msqrt></mfenced><mo>&#xA0;</mo></mrow><mspace linebreak="newline"/><mo>&#x21D2;</mo><mo>&#xA0;</mo><mfrac><mi>dy</mi><mi>dx</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mfrac><mrow><mo>-</mo><mi>sin</mi><mfenced><msqrt><mi mathvariant="normal">x</mi></msqrt></mfenced></mrow><mrow><mn>2</mn><msqrt><mi mathvariant="normal">x</mi></msqrt></mrow></mfrac></math>

9. Prove that the function f given by f(x) = |x - 1|, x∈R is not differentiable at x = 1.

Solun:- Let f(x) = |x - 1|

<math xmlns="http://www.w3.org/1998/Math/MathML"><mo>&#x21D2;</mo><mo>&#xA0;</mo><mi mathvariant="normal">f</mi><mfenced><mi mathvariant="normal">x</mi></mfenced><mo>=</mo><mfenced open="{" close=""><mtable columnalign="left"><mtr><mtd><mi mathvariant="normal">x</mi><mo>-</mo><mn>1</mn><mo>,</mo><mo>&#xA0;</mo><mo>&#xA0;</mo><mo>&#xA0;</mo><mo>&#xA0;</mo><mo>&#xA0;</mo><mo>&#xA0;</mo><mo>&#xA0;</mo><mo>&#xA0;</mo><mo>&#xA0;</mo><mo>&#xA0;</mo><mi>if</mi><mo>&#xA0;</mo><mi mathvariant="normal">x</mi><mo>&#x2265;</mo><mn>1</mn></mtd></mtr><mtr><mtd><mo>-</mo><mfenced><mrow><mi mathvariant="normal">x</mi><mo>-</mo><mn>1</mn></mrow></mfenced><mo>,</mo><mo>&#xA0;</mo><mo>&#xA0;</mo><mi>if</mi><mo>&#xA0;</mo><mi mathvariant="normal">x</mi><mo>&lt;</mo><mn>1</mn></mtd></mtr></mtable></mfenced></math>

We know for differentiability:-

R.H.D = L.H.D

<math xmlns="http://www.w3.org/1998/Math/MathML"><mo>&#x21D2;</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mfrac><mrow><mi mathvariant="normal">f</mi><mfenced><mrow><mi mathvariant="normal">x</mi><mo>+</mo><mi mathvariant="normal">h</mi></mrow></mfenced><mo>-</mo><mi mathvariant="normal">f</mi><mfenced><mi mathvariant="normal">x</mi></mfenced></mrow><mi mathvariant="normal">h</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mfrac><mrow><mi mathvariant="normal">f</mi><mfenced><mrow><mi mathvariant="normal">x</mi><mo>-</mo><mi mathvariant="normal">h</mi></mrow></mfenced><mo>-</mo><mi mathvariant="normal">f</mi><mfenced><mi mathvariant="normal">x</mi></mfenced></mrow><mrow><mo>-</mo><mi mathvariant="normal">h</mi></mrow></mfrac></math>

R.H.D:-  

At x>1

<math xmlns="http://www.w3.org/1998/Math/MathML"><mo>=</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mfrac><mrow><mi mathvariant="normal">f</mi><mfenced><mrow><mi mathvariant="normal">x</mi><mo>+</mo><mi mathvariant="normal">h</mi></mrow></mfenced><mo>-</mo><mi mathvariant="normal">f</mi><mfenced><mi mathvariant="normal">x</mi></mfenced></mrow><mi mathvariant="normal">h</mi></mfrac><mspace linebreak="newline"/><mo>=</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mfrac><mrow><mfenced><mrow><mi mathvariant="normal">x</mi><mo>+</mo><mi mathvariant="normal">h</mi><mo>-</mo><mn>1</mn></mrow></mfenced><mo>-</mo><mfenced><mrow><mi mathvariant="normal">x</mi><mo>-</mo><mn>1</mn></mrow></mfenced></mrow><mi mathvariant="normal">h</mi></mfrac><mspace linebreak="newline"/><mo>=</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mo>&#xA0;</mo><mfrac><mi mathvariant="normal">h</mi><mi mathvariant="normal">h</mi></mfrac><mspace linebreak="newline"/><mo>=</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mo>&#xA0;</mo><mn>1</mn></math>

Put h = 0

= 1

L.H.D:-  

At x<1

<math xmlns="http://www.w3.org/1998/Math/MathML"><mo>=</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mfrac><mrow><mi mathvariant="normal">f</mi><mfenced><mrow><mi mathvariant="normal">x</mi><mo>-</mo><mi mathvariant="normal">h</mi></mrow></mfenced><mo>-</mo><mi mathvariant="normal">f</mi><mfenced><mi mathvariant="normal">x</mi></mfenced></mrow><mrow><mo>-</mo><mi mathvariant="normal">h</mi></mrow></mfrac><mspace linebreak="newline"/><mo>=</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mfrac><mrow><mo>-</mo><mfenced><mrow><mi mathvariant="normal">x</mi><mo>-</mo><mi mathvariant="normal">h</mi><mo>-</mo><mn>1</mn></mrow></mfenced><mo>+</mo><mfenced><mrow><mi mathvariant="normal">x</mi><mo>-</mo><mn>1</mn></mrow></mfenced></mrow><mrow><mo>-</mo><mi mathvariant="normal">h</mi></mrow></mfrac><mspace linebreak="newline"/><mo>=</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mo>&#xA0;</mo><mfrac><mi mathvariant="normal">h</mi><mrow><mo>-</mo><mi mathvariant="normal">h</mi></mrow></mfrac><mspace linebreak="newline"/><mo>=</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mo>&#xA0;</mo><mo>-</mo><mn>1</mn></math>

Put h = 0

= - 1

R.H.D L.H.D

Hence given function is not differentiable at x = 1.

10. Prove that the greater integer function defined by f(x) = [x], 0<x<3 is not differentiable at x = 1 and at x=2.

Solun:- Let f(x) = [x]

We know for differentiability:-

R.H.D = L.H.D

<math xmlns="http://www.w3.org/1998/Math/MathML"><mo>&#x21D2;</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mfrac><mrow><mi mathvariant="normal">f</mi><mfenced><mrow><mi mathvariant="normal">x</mi><mo>+</mo><mi mathvariant="normal">h</mi></mrow></mfenced><mo>-</mo><mi mathvariant="normal">f</mi><mfenced><mi mathvariant="normal">x</mi></mfenced></mrow><mi mathvariant="normal">h</mi></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mfrac><mrow><mi mathvariant="normal">f</mi><mfenced><mrow><mi mathvariant="normal">x</mi><mo>-</mo><mi mathvariant="normal">h</mi></mrow></mfenced><mo>-</mo><mi mathvariant="normal">f</mi><mfenced><mi mathvariant="normal">x</mi></mfenced></mrow><mrow><mo>-</mo><mi mathvariant="normal">h</mi></mrow></mfrac></math>

At x = 1

R.H.D:-  

<math xmlns="http://www.w3.org/1998/Math/MathML"><mo>=</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mfrac><mrow><mi mathvariant="normal">f</mi><mfenced><mrow><mi mathvariant="normal">x</mi><mo>+</mo><mi mathvariant="normal">h</mi></mrow></mfenced><mo>-</mo><mi mathvariant="normal">f</mi><mfenced><mi mathvariant="normal">x</mi></mfenced></mrow><mi mathvariant="normal">h</mi></mfrac><mspace linebreak="newline"/><mo>=</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mfrac><mrow><mfenced open="[" close="]"><mrow><mi mathvariant="normal">x</mi><mo>+</mo><mi mathvariant="normal">h</mi></mrow></mfenced><mo>-</mo><mfenced open="[" close="]"><mi mathvariant="normal">x</mi></mfenced></mrow><mi mathvariant="normal">h</mi></mfrac><mspace linebreak="newline"/><mo>=</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mfrac><mrow><mfenced open="[" close="]"><mrow><mn>1</mn><mo>+</mo><mi mathvariant="normal">h</mi></mrow></mfenced><mo>-</mo><mfenced open="[" close="]"><mn>1</mn></mfenced></mrow><mi mathvariant="normal">h</mi></mfrac><mspace linebreak="newline"/><mo>=</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mo>&#xA0;</mo><mfrac><mrow><mn>1</mn><mo>-</mo><mn>1</mn></mrow><mi mathvariant="normal">h</mi></mfrac><mspace linebreak="newline"/><mo>=</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mo>&#xA0;</mo><mn>0</mn></math>

Put h = 0

= 0

L.H.D:-

<math xmlns="http://www.w3.org/1998/Math/MathML"><mo>=</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mfrac><mrow><mi mathvariant="normal">f</mi><mfenced><mrow><mi mathvariant="normal">x</mi><mo>-</mo><mi mathvariant="normal">h</mi></mrow></mfenced><mo>-</mo><mi mathvariant="normal">f</mi><mfenced><mi mathvariant="normal">x</mi></mfenced></mrow><mrow><mo>-</mo><mi mathvariant="normal">h</mi></mrow></mfrac><mspace linebreak="newline"/><mo>=</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mfrac><mrow><mfenced open="[" close="]"><mrow><mi mathvariant="normal">x</mi><mo>-</mo><mi mathvariant="normal">h</mi></mrow></mfenced><mo>-</mo><mfenced open="[" close="]"><mi mathvariant="normal">x</mi></mfenced></mrow><mrow><mo>-</mo><mi mathvariant="normal">h</mi></mrow></mfrac><mspace linebreak="newline"/><mo>=</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mfrac><mrow><mfenced open="[" close="]"><mrow><mn>1</mn><mo>-</mo><mi mathvariant="normal">h</mi></mrow></mfenced><mo>-</mo><mfenced open="[" close="]"><mn>1</mn></mfenced></mrow><mrow><mo>-</mo><mi mathvariant="normal">h</mi></mrow></mfrac><mspace linebreak="newline"/><mo>=</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mo>&#xA0;</mo><mfrac><mrow><mfenced><mrow><mn>1</mn><mo>-</mo><mn>1</mn></mrow></mfenced><mo>-</mo><mn>1</mn></mrow><mrow><mo>-</mo><mi mathvariant="normal">h</mi></mrow></mfrac><mspace linebreak="newline"/><mo>=</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mo>&#xA0;</mo><mfrac><mn>1</mn><mi mathvariant="normal">h</mi></mfrac></math>

Put h = 0

L.H.D is not defined.

Hence given function is not differentiable at x = 1.

At x = 2

R.H.D:-  

<math xmlns="http://www.w3.org/1998/Math/MathML"><mo>=</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mfrac><mrow><mi mathvariant="normal">f</mi><mfenced><mrow><mi mathvariant="normal">x</mi><mo>+</mo><mi mathvariant="normal">h</mi></mrow></mfenced><mo>-</mo><mi mathvariant="normal">f</mi><mfenced><mi mathvariant="normal">x</mi></mfenced></mrow><mi mathvariant="normal">h</mi></mfrac><mspace linebreak="newline"/><mo>=</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mfrac><mrow><mfenced open="[" close="]"><mrow><mi mathvariant="normal">x</mi><mo>+</mo><mi mathvariant="normal">h</mi></mrow></mfenced><mo>-</mo><mfenced open="[" close="]"><mi mathvariant="normal">x</mi></mfenced></mrow><mi mathvariant="normal">h</mi></mfrac><mspace linebreak="newline"/><mo>=</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mfrac><mrow><mfenced open="[" close="]"><mrow><mn>2</mn><mo>+</mo><mi mathvariant="normal">h</mi></mrow></mfenced><mo>-</mo><mfenced open="[" close="]"><mn>2</mn></mfenced></mrow><mi mathvariant="normal">h</mi></mfrac><mspace linebreak="newline"/><mo>=</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mo>&#xA0;</mo><mfrac><mrow><mn>2</mn><mo>-</mo><mn>2</mn></mrow><mi mathvariant="normal">h</mi></mfrac><mspace linebreak="newline"/><mo>=</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mo>&#xA0;</mo><mn>0</mn></math>

Put h = 0

= 0

L.H.D:-

<math xmlns="http://www.w3.org/1998/Math/MathML"><mo>=</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mfrac><mrow><mi mathvariant="normal">f</mi><mfenced><mrow><mi mathvariant="normal">x</mi><mo>-</mo><mi mathvariant="normal">h</mi></mrow></mfenced><mo>-</mo><mi mathvariant="normal">f</mi><mfenced><mi mathvariant="normal">x</mi></mfenced></mrow><mrow><mo>-</mo><mi mathvariant="normal">h</mi></mrow></mfrac><mspace linebreak="newline"/><mo>=</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mfrac><mrow><mfenced open="[" close="]"><mrow><mi mathvariant="normal">x</mi><mo>-</mo><mi mathvariant="normal">h</mi></mrow></mfenced><mo>-</mo><mfenced open="[" close="]"><mi mathvariant="normal">x</mi></mfenced></mrow><mrow><mo>-</mo><mi mathvariant="normal">h</mi></mrow></mfrac><mspace linebreak="newline"/><mo>=</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mfrac><mrow><mfenced open="[" close="]"><mrow><mn>2</mn><mo>-</mo><mi mathvariant="normal">h</mi></mrow></mfenced><mo>-</mo><mfenced open="[" close="]"><mn>2</mn></mfenced></mrow><mrow><mo>-</mo><mi mathvariant="normal">h</mi></mrow></mfrac></math>

<math xmlns="http://www.w3.org/1998/Math/MathML"><mo>=</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mo>&#xA0;</mo><mfrac><mrow><mfenced><mrow><mn>2</mn><mo>-</mo><mn>1</mn></mrow></mfenced><mo>-</mo><mn>2</mn></mrow><mrow><mo>-</mo><mi mathvariant="normal">h</mi></mrow></mfrac><mspace linebreak="newline"/><mo>=</mo><mo>&#xA0;</mo><munder><mi>lim</mi><mrow><mi mathvariant="normal">h</mi><mo>&#x2192;</mo><mn>0</mn></mrow></munder><mo>&#xA0;</mo><mfrac><mn>1</mn><mi mathvariant="normal">h</mi></mfrac></math>

Put h = 0

L.H.D is not defined.

Hence given function is not differentiable at x = 2.



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