Miscellaneous Exercise
Integrate the functions in Exercises 1 to 24.
Solun:- Let f(x) =
Integrate f(x):-
By Partial Fraction:-
⇒ 1 = A(1 - x2) + B(x)(1 + x) + C(x)(1 - x)......(1)
Put x = 0 in eq. 1:-
⇒ 1 = A(1)
⇒ A = 1
Put x = 1 in eq. 1:-
⇒ 1 = B(1)(2)
⇒ B = 1/2
Put x = - 1 in eq. 1:-
⇒ 1 = C(-1)(2)
⇒ C = - 1/2
We know that:-
We know that:-
⇒ log m - log n = log (m/n)
⇒ log mn = n.log m
⇒ log m + log n = log (mn)
Solun:- Let f(x) =
Integrate f(x):-
We know that:-
Solun:- Let f(x) =
Integrate f(x):-
Let x = a/t
Differentiate w.r.t. to t:-
⇒ dx = - a/t2.dt
We know that:-
Put the value of t:-
Solun:- Let f(x) =
Integrate f(x):-
Let 1 + 1/x4 = t4
Differentiate w.r.t. to t:-
⇒ (0 + (-4/x5)).dx = 4t3.dt
⇒ 1/x5.dx = (-4t3/4).dt
⇒ 1/x5.dx = -t3.dt
Put the value of t:-
Solun:- Let f(x) =
Integrate f(x):-
Let x = t6
Differentiate w.r.t. to t:-
⇒ dx = 6t5.dt
On Dividing:-
Put the value of t:-
Solun:- Let f(x) =
Integrate f(x):-
By Partial Fraction:-
⇒ 5x = A(x2 + 9) + (Bx + C)(x + 1).....(1)
Put x = -1 in eq. 1:-
⇒ -5 = A(10)
⇒ A = -1/2
Put x = 0 in eq. 1:-
⇒ 0 = A(9) + C(1)
⇒ 0 =(-1/2)(9) + C
⇒ 0 =(-9/2) + C
⇒ C = 9/2
Put x = 1 in eq. 1:-
⇒ 5 = A(10) + (B + C)(2)
⇒ 5 = (-1/2)(10) + (B + 9/2)(2)
⇒ 5 = -5 + 2B + 9
⇒ 1 = 2B
⇒ B = 1/2
We know that:-
Solun:- Let f(x) =
Integrate f(x):-
Let x - a = t
Differentiate w.r.t. to t:-
⇒ dx = dt
We know that:-
Put the value of t:-
Solun:- Let f(x) =
Integrate f(x):-
We know that:-
Solun:- Let f(x) =
Integrate f(x):-
Let sin x = t
Differentiate w.r.t. to t:-
⇒ (cos x).dx = dt
We know that:-
Put the value of t:-
Solun:- Let f(x) =
Integrate f(x):-
We know that:-
⇒ cos2x - sin2x = cos 2x
We know that:-
Solun:- Let f(x) =
Integrate f(x):-
We know that:-
Solun:- Let f(x) =
Integrate f(x):-
Let x4 = t
Differentiate w.r.t. to t:-
⇒ 4x3.dx = dt
⇒ x3.dx = (1/4).dt
We know that:-
Put the value of t:-
Solun:- Let f(x) =
Integrate f(x):-
Let ex = t
Differentiate w.r.t. to t:-
⇒ ex.dx = dt
By Partial Fraction:-
⇒ 1 = A(2 + t) + B(1 + t)....(1)
Put t = - 1 in eq. 1:-
⇒ 1 = A(1)
⇒ A = 1
Put t = - 2 in eq. 1:-
⇒ 1 = B(-1)
⇒ B = - 1
We know that:-
Put the value of t:-
Solun:- Let f(x) =
Integrate f(x):-
Put x2 = t
By Partial Fraction:-
⇒ 1 = A(t + 4) + B(t + 1)....(1)
Put t = - 1 in eq. 1:-
⇒ 1 = A(3)
⇒ A = 1/3
Put t = - 4 in eq. 1:-
⇒ 1 = B(-3)
⇒ B = - 1/3
We know that:-
Solun:- Let f(x) = cos3x.elog sinx
Integrate f(x):-
Let cos x = t
Differentiate w.r.t. to t:-
⇒ - sin x.dx = dt
⇒ sin x.dx = - dt
We know that:-
Put the value of t:-
Solun:- Let f(x) =
Integrate f(x):-
Let x4 + 1 = t
Differentiate w.r.t. to t:-
⇒ 4x3.dx = dt
⇒ x3.dx = (1/4).dt
We know that:-
Put the value of t:-
Solun:- Let f(x) =
Integrate f(x):-
Let f(ax + b) = t
Differentiate w.r.t. to t:-
⇒ a.f’(ax + b).dx = dt
⇒ f’(ax + b).dx = (1/a).dt
We know that:-
Put the value of t:-
Solun:- Let f(x) =
Integrate f(x):-
Let cos α + cot x.sin α = t
Differentiate w.r.t. to t:-
⇒ - sin α.cosec2x.dx = dt
⇒ cosec2x.dx = (-1/sin α).dt
We know that:-
Put the value of t:-
Solun:- Let f(x) =
Integrate f(x):-
We know that:-
sin-1x + cos-1x = π/2
Let sin-1√x = t
⇒ √x = sin t
⇒ x = sin2 t
Differentiate w.r.t. to t:-
⇒ dx = 2sint.cost.dt
⇒ dx = sin 2t.dt
We know that:-
Put the value of t:-
⇒ cos t = √(1-x)
⇒ sin 2t = 2√(x-x2)
⇒ cos 2t = 1 - 2x
Solun:- Let f(x) =
Integrate f(x):-
Let x = cos2y
Differentiate w.r.t. to y:-
⇒ dx = 2cosy.(-siny).dy
⇒ dx = - sin 2y.dy
We know that:-
⇒ cos 2y = 2cos2y - 1
⇒ cos 2y = 1 - 2sin2y
We know that:-
Put the value of y:-
⇒ cos y = √x
⇒ sin y = √(1-x)
⇒ sin 2y = 2√(x - x2)
Solun:- Let f(x) =
Integrate f(x):-
We know that:-
Let f(x) = tan x
⇒ f’(x) = sec2x
Solun:- Let f(x) =
Integrate f(x):-
By Partial Fraction:-
⇒ x2+x+1 = A(x + 1)(x + 2) + B(x + 2) + C(x + 1)2......(1)
Put x = -1 in eq. 1:-
⇒ 1 = B(1)
⇒ B = 1
Put x = -2 in eq. 1:-
⇒ 3 = C(1)
⇒ C = 3
Put x = 0 in eq. 1:-
⇒ 1 = 2A + 2B + C
⇒ 1 = 2A + 2 + 3
⇒ 2A = - 4
⇒ A = -2
We know that:-
Solun:- Let f(x) =
Integrate f(x):-
Let x = cos y
Differentiate w.r.t. to y:-
⇒ dx = -siny.dy
We know that:-
According to ILATE:- u = y and v = sin y
We know that:-
Put the value of y:-
⇒ cos y = x
⇒ sin y = √(1-x2)
Solun:- Let f(x) =
Integrate f(x):-
Let 1+1/x2 = t
Differentiate w.r.t. to t:-
⇒ -2/x3.dx = dt
⇒ 1/x3.dx = (-1/2).dt
We know that:-
According to ILATE:- u = log t and v = √t
Put the value of t:-
Evaluate the definite integrals in Exercises 25 to 33.
Solun:- Let f(x) =
Integrate f(x):-
We know that:-
Let f(x) = - cot (x/2)
Then
Solun:- Let f(x) =
Integrate f(x):-
Let tan2x = t…....(1)
Differentiate w.r.t. to t:-
⇒ 2tan x.sec2x.dx = dt
⇒ tan x.sec2x.dx = (1/2).dt
Limits Change:-
Put x = 0 in eq. 1:-
⇒ t = 0
Put x = π/4 in eq. 1:-
⇒ t = 1
We know that:-
Solun:- Let f(x) =
Integrate f(x):-
Let tan x = t…....(1)
Differentiate w.r.t. to t:-
⇒ sec2x.dx = dt
Limits change:-
Put x = 0 in eq. 1:-
⇒ t = 0
Put x = π/2 in eq. 1:-
⇒ t = ∞
We know that:-
Solun:- Let f(x) =
Integrate f(x):-
Let sin x - cos x = t…....(1)
Differentiate w.r.t. to t:-
⇒ (cos x + sin x).dx = dt
Limits change:-
Put x = π/6 in eq. 1:-
⇒ t = (1 - √3)/2
Put x = π/3 in eq. 1:-
⇒ t = (√3 - 1)/2
We know that:-
We know that:-
sin-1(-x) = -sin-1(x)
Solun:- Let f(x) =
Integrate f(x):-
We know that:-
Solun:- Let f(x) =
Integrate f(x):-
Let sin x - cos x = t…....(1)
Differentiate w.r.t. to t:-
⇒ (cos x + sin x).dx = dt
Limits change:-
Put x = 0 in eq. 1:-
⇒ t = - 1
Put x = π/4 in eq. 1:-
⇒ t = 0
We know that:-
Solun:- Let f(x) = sin 2x.tan-1(sin x)
Integrate f(x):-
Let sin x = t…....(1)
Differentiate w.r.t. to t:-
⇒ cos x.dx = dt
Limits change:-
Put x = 0 in eq. 1:-
⇒ t = 0
Put x = π/2 in eq. 1:-
⇒ t = 1
We know that:-
According to ILATE:- u = tan-1t and v = t
We know that:-
We know that:-
tan-1(-x) = tan-1x
Solun:- Let f(x) =
Integrate f(x):-
By Property:-
Add eq. 1 and 2:-
We know that:-
Solun:- Let f(x) = [|x - 1| + |x - 2| + |x - 3|]
Integrate f(x):-
Calculating I1:-
Calculating I2:-
Calculating I3:-
Put the value of I1, I2, and I3 in eq. 1:-
Prove the following (Exercises 34 to 39)
Solun:- Let f(x) =
Integrate f(x):-
By Partial Fraction:-
⇒ 1 = A(x)(x + 1) + B(x + 1) + C(x2)......(1)
Put x = 0 in eq. 1:-
⇒ 1 = B(1)
⇒ B = 1
Put x = -1 in eq. 1:-
⇒ 1 = C(1)
⇒ C = 1
Put x = 1 in eq. 1:-
⇒ 1 = A(1)(2) + B(2) + C(1)
⇒ 1 = A(1)(2) + 1(2) + 1(1)
⇒ 1 - 3 = A(1)(2)
⇒ A = - 1
We know that:-
Hence Proved...
Solun:- Let f(x) = x.ex
Integrate f(x):-
We know that:-
According to ILATE:- u = x and v = ex
Hence Proved…....
Solun:- Let f(x) = x17.cos4x
Integrate f(x):-
By Property:-
f(-x) = (-x)17.[cos (-x)]4 = - x17.cos4x
f(-x) = - f(x)
Hence Proved….
Solun:- Let f(x) = sin3x
Integrate f(x):-
We know that:-
sin 3x = 3sinx - 4sin3x
We know that:-
Hence Proved…
Solun:- Let f(x) = 2tan3x
Integrate f(x):-
Let tan x = t…....(1)
Differentiate w.r.t. to t:-
⇒ sec2x.dx = dt
Limits Change:-
Put x = 0 in eq. 1:-
⇒ t = 0
Put x = π/4 in eq. 1:-
⇒ t = 1
We know that:-
Hence Proved…
Solun:- Let f(x) = sin-1x
Integrate f(x):-
Let sin-1x = t and x = sin t
Differentiate w.r.t. to t:-
⇒ dx = cos t.dt
Limits Change:-
Put x = 0 in eq. 1:-
⇒ t = 0
Put x = 1 in eq. 1:-
⇒ t = Ï€/2
We know that:-
According to ILATE:- u = t and v = cos t
We know that:-
Hence Proved…
Choose the correct answer in Exercises 41 to 44.
is equal to
Solun:- Let f(x) =
Integrate f(x):-
Let ex = t
Differentiate w.r.t. to t:-
⇒ ex.dx = dt
We know that:-
Put the value of t:-
The correct answer is A.
is equal to
Solun:- Let f(x) =
Integrate f(x):-
We know that:-
cos 2x = cos2x - sin2x
Let sin x + cos x = t
Differentiate w.r.t. to t:-
⇒ (cos x - sin x).dx = dt
We know that:-
Put the value of t:-
The correct answer is B.
43. If f(a+b-x) = f(x), then is equal to
Solun:- Given
By Property:-
Given f(a+b-x) = f(x)
Add eq. 1 and 2:-
The correct answer is D.
44. The value of is
Solun:- Given
We know that:-
By Property:-
Add eq. 1 and 2:-
The correct answer is B.
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