Exercise 7.3
Find the integrals of the functions in Exercises 1 to 22:
1. sin2(2x+5)
Solun:- Let f(x) = sin2(2x+5)
Integrate f(x):-
We know that cos 2x = 1 - 2sin2x
Let 4x + 10 = t
Differentiate w.r.t to t:-
⇒ 4.dx = dt
⇒ dx = (1/4).dt
We know that:-
Put the value of t:-
2. sin 3x.cos 4x
Solun:- Let f(x) = sin 3x.cos 4x
Integrate f(x):-
We know that 2sinA.cosB = sin(A+B)+sin(A-B)
Let 7x = t
Differentiate w.r.t to t:-
⇒ 7.dx = dt
⇒ dx = (1/7).dt
We know that:-
Put the value of t:-
3. cos 2x.cos 4x.cos 6x
Solun:- Let f(x) = cos 2x.cos 4x.cos 6x
Integrate f(x):-
We know that 2cosA.cosB = cos(A+B)+cos(A-B)
We know that:- 2cosA.cosB = cos(A+B)+cos(A-B)
cos 2x = 2cos2x - 1
We know that:-
Put the value of t:-
4. sin3(2x + 1)
Solun:- Let f(x) = sin3(2x + 1)
Integrate f(x):-
Method 1:-
We know that:- sin 3x = 3sin x - 4sin3x
Let 6x + 3 = t
Differentiate w.r.t to t:-
⇒ 6.dx = dt
⇒ dx = (1/6).dt
We know that:-
Put the value of t:-
Method 2:-
Let cos (2x+1) = t
Differentiate w.r.t to t:-
⇒ -2.sin(2x+1).dx = dt
⇒ sin(2x+1).dx = (-1/2). dt
We know that:-
Put the value of t:-
5. sin3x.cos3x
Solun:- Let f(x) = sin3x.cos3x
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:-
6. sin x.sin 2x.sin 3x
Solun:- Let f(x) = sin x.sin 2x.sin 3x
Integrate f(x):-
We know that 2sinA.sinB = cos(A-B) - cos(A+B)
We know that:- 2cosA.sinB = sin(A+B) - sin(A-B)
We know that:-
7. sin 4x.sin 8x
Solun:- Let f(x) = sin 4x.sin 8x
Integrate f(x):-
We know that 2sinA.sinB = cos(A-B) - cos(A+B)
We know that:-
Solun:- Let f(x) =
Integrate f(x):-
We know that 1 - cosx = 2sin2(x/2)
⇒ 1 + cos x = 2cos2(x/2)
We know that:- sec2x - tan2x = 1
We know that:-
Solun:- Let f(x) =
Integrate f(x):-
We know that cosx = 1 - 2sin2(x/2)
⇒ 1 + cos x = 2cos2(x/2)
We know that:- sec2x - tan2x = 1
We know that:-
Solun:- Let f(x) = sin4x
Integrate f(x):-
We know that 2.sin2x = 1 - cos 2x
We know that:- 2.cos2x = 1 + cos 2x
We know that:-
Solun:- Let f(x) = cos42x
Integrate f(x):-
We know that 2.cos2x = 1 + cos 2x
We know that:- 2.cos2x = 1 + cos 2x
We know that:-
Solun:- Let f(x) =
Integrate f(x):-
We know that sin2x = 1 - cos2x
We know that:-
Solun:- Let f(x) =
Integrate f(x):-
We know that
We know that:-
We know that:-
2cosA.cosB = cos(A+B) + cos(A-B)
We know that:-
Solun:- Let f(x) =
Integrate f(x):-
Let sin x + cos x = t
Differentiate w.r.t to t:-
⇒ (cos x - sin x).dx = dt
We know that:-
Put that value of t:-
Solun:- Let f(x) = tan32x.sec2x
Integrate f(x):-
We know that:-
sec2x - tan2x = 1
Let sec 2x = t
Differentiate w.r.t to t:-
⇒ 2.sec 2x.tan 2x.dx = dt
⇒ sec 2x.tan 2x.dx = (1/2).dt
We know that:-
Put that value of t:-
Solun:- Let f(x) = tan4x
Integrate f(x):-
We know that:-
sec2x - tan2x = 1
Let tan x = t
Differentiate w.r.t to t:-
⇒ sec2x.dx = dt
We know that:-
Put that value of t:-
Solun:- Let f(x) =
Integrate f(x):-
We know that:-
Solun:- Let f(x) =
Integrate f(x):-
We know that:-
cos 2x = 1 - 2sin2x
We know that:-
Solun:- Let f(x) =
Integrate f(x):-
We know that:-
sec2x - tan2x = 1
Let tan x = t
Differentiate w.r.t to t:-
⇒ sec2x.dx = dt
We know that:-
Put that value of t:-
Solun:- Let f(x) =
Integrate f(x):-
We know that:-
cos 2x = cos2x - sin2x
Let cos x + sinx = t
Differentiate w.r.t to t:-
⇒ (- sin x+cos x).dx = dt
We know that:-
Put value of t in this eq. :-
Solun:- Let f(x) =
Integrate f(x):-
We know that:-
We know that:-
Solun:- Let f(x) =
Integrate f(x):-
We know that:-
sin (A - B) = sinA.cosB - cosA.sinB
We know that:-
Choose the correct answer in Exercises 23 and 24.
is equal to
(A) tan x + cot x + C
(B) tan x + cosec x + C
(C) - tan x + cot x + C
(D) tan x + sec x + C
Solun:- Let f(x) =
Integrate f(x):-
We know that:-
The correct answer is A.
is equal to
(A) - cot (e.xx) + C
(B) tan (x.ex) + C
(C) tan (ex) + C
(D) cot (ex) + C
Solun:- Let f(x) =
Integrate f(x):-
Let ex.x = t
Differentiate w.r.t to t:-
⇒ (ex.1 + x.ex).dx = dt
⇒ ex.(1 + x).dx = dt
We know that:-
Put the value of t in this eq. :-
The correct answer is B.
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