Find an anti derivative (or integral) of the following functions by the method of inspection.
Question 1 sin 2x
Solution :
The anti derivative of sin 2x is a function of x whose derivative is sin 2x.
It is known that,
herefore, the anti derivative of sin 2x is -1/2 cos 2x.
Question 2. cos 3x
Solution :
The anti derivative of cos 3x is a function of x whose derivative is cos 3x.
It is known that,
Therefore, the anti derivative of cos 3x is 1/3 sin 3x.
Question 3. e2x
Solution :
The anti derivative of e2x is the function of x whose derivative is e2x.
It is known that,
Therefore, the anti derivative of e2x is 1/2 e2x.
Question 4. (ax + b)2
Solution :
The anti derivative of (ax + b)2 is the function of x whose derivative is (ax + b)2.
It is known that,
Question 5. sin 2x – 4 e3x
Solution :
The anti derivative of sin 2x – 4 e3x is the function of x whose derivative is sin 2x – 4 e3x
It is known that,
Evaluate the following integrals in Exercises 6 to 11.
Question 6. ∫(4e3x+ 1) dx
Solution
Question 7.
Solution :
Question 8.
Solution
Question 9.
Solution :
Question 10.
Solution :
Question 11.
Solution :
Evaluate the following integrals in Exercises 12 to 16.
Question 12.
Solution :
Question 13.
Solution :
Question 14. ∫(1 – x)√x dx
Solution : ∫(1 – x)√x dx
Question 15.
Solution :
Question 16.
Solution
Evaluate the following integrals in Exercises 17 to 20.
Question 17.
Solution
Question 18.
Solution
Question 19.
Solution :
Question 20.
Solution
Question 21. Choose the correct answer:
The anti derivative of equals.
Solution
Therefore, option (C) is correct.
Question 22. Choose the correct answer:
If such that f(2) = 0 Then f is:
Solution :
It is given that,
Therefore, option (A) is correct.
Exercise 7.2 Page: 240
Integrate the functions in Exercise 1 to 8.
Question 1.
Solution :
Let 1 + x2 = t
∴2x dx = dt
Question 2.
Solution :
Let log |x| = t
∴1/xdx=dt
Question 3.
Solution :
Question 4. sin x ⋅ sin (cos x)
Solution :
sin x ⋅ sin (cos x)
Let cos x = t
∴−sin xdx=dt
Question 5. sin(ax + b) cos(ax + b)
Solution :
Questionc 6. √ax + b
Solution :
Let ax + b = t
⇒ adx = dt
Question 7. x√x + 2
Solution :
Let (x + 2) = t
∴ dx = dt
Question8. x√1+2x2
Solution :
Let 1 + 2x2 = t
∴ 4xdx = dt
Integrate the functions in Exercise 9 to 17.
Question 9.
Solution :
Question 10.
Solution :
Question 11.
Solution :
Question 12.
Solution :
Let x3 – 1 = t
∴ 3x2 dx = dt
Question 13.
Solution :
Let 2 + 3x3 = t
∴ 9x2 dx = dt
Question14.
Solution :
Let log x = t
∴ 1/x dx = dt
Question 15. x/9 – 4x2
Solution :
Let 9 – 4x2 = t
∴ −8x dx = dt
Question 16.
Solution :
Let 2x + 3 = t
∴ 2dx = dt
Question17.
Solution :
Let x2 = t
∴ 2xdx = dt
Integrate the functions in Exercise 18 to 26.
Question 18.
Solution :
Question 19.
Solution :
Dividing numerator and denominator by ex, we obtain
Question20.
Solution :
Question 21. tan2 (2x – 3)
Solution :
Question 22. sec2 (7 – 4x)
Solution :
Let 7 − 4x = t
∴ −4dx = dt
Question 23.
Solution :
Question 24.
Solution :
Question 25.
Solution :
Question 26.
Solution :
Let √x = t
Integrate the functions in Exercise 27 to 37.
Question 27.
Solution :
Let sin 2x = t
Question 28.
Solution :
Let 1 + sin x = t
∴ cos x dx = dt
Question 29. cot x log sin x
Solution :
Let log sin x = t
Question 30. sin x/1 + cos x
Solution :
Let 1 + cos x = t
∴ −sin x dx = dt
Question 31. sin x/(1 + cos x)2
Solution :
Let 1 + cos x = t
∴ −sin x dx = dt
Question32.1/1+cot x
Solution :
Question 33. 1/1 – tan x
Solution :
Question 34.
Solution :
Question 35.
Solution :
Let 1 + log x = t
∴1/xdx=dt
Question 36.
Solution :
Question 37.
Solution :
Let x4 = t
∴ 4x3 dx = dt
Choose the correct answer in Exercise 38 and 39.
Question 38. equals
(A)10x –x10 +C
(B) 10x +x10 +C
(C) (10x –x10)-1 +C
(D) log(10x + x10) + C
Solution :
Therefore, option (D) is correct.
Question 39.equals
(A) tanx+cotx+C
(B)tanx–cotx+C
(C)tanxcotx+C
(D) tan x – cot 2x + C
Solution :
Therefore, option (B) is correct.
Exercise 7.3 Page: 243
Find the integrals of the following functions in Exercises 1 to 9.
Question 1. sin2(2x + 5)
Solution :
Question 2. sin 3x cos4x
Solution :
Question 3. cos 2x cos 4x cos 6x
Solution :
Question 4. sin3 (2x + 1)
Question 5. sin3 x cos3 x
Question 6. sin x sin 2x sin 3x
Question 7. sin 4x sin 8x
Solution: Itisknownthat,
sin A . sin B = 12cosA-B-cosA+B
∴∫sin4x sin8x dx=∫12cos4x-8x-cos4x+8xdx
=12∫cos-4x-cos12xdx
=12∫cos4x-cos12xdx
=12sin4x4-sin12x12+C
Question 8.
Question 9.
Solution :
Find the integrals of the following functions in Exercises 10 to 18.
Question 10. sin4 x
Solution :
Question 11. cos4 2x
Solution :
Question 12.
Solution :
Question13.
Question 14.
Solution :
Question 15. tan3 2x sec2x
Solution :
Question 16. tan4x
Solution :Question 17.
Solution :
Question 18.
Solution :
.
Question 19.
Solution :
Question20.
Solution :20
Question 21. sin−1 (cos x)
Solution :
Question 22.
Solution : Choose the correct answer in Exercise 23 and 24.
Question 23.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
Solution :
Therefore, option (A) is correct.
Question 24. is equal to:
A. − cot (exx) + C
B. tan (xex) + C
C. tan (ex) + C
D. cot (ex) + C
Solution :
Let I =
Let exx = t
Therefore, option (B) is correct.
Exercise 7.4 Page: 251
Integrate the following functions in Exercises 1 to 9.
Question 1.
Solution :
Let x3 = t
∴ 3x2 dx = dt
Question 2.
Solution :
Let 2x = t
∴ 2dx = dt
Question 3.
Solution :
Let 2 − x = t
⇒ −dx = dt
Question 4.
Solution :
Let 5x = t
∴ 5dx = dt
Question 5.
Solution :
Question 6.
Solution :
Let x3 = t
∴ 3x2 dx = dt
Question 7.
Solution :
Question 8.
Solution :
Let x3 = t
∴ 3x2 dx = dt
Question 9.
Solution :
Let tan x = t
∴ sec2x dx = dt
Integrate the following functions in Exercises 10 to 18.
Question 10.
Solution :
Question 11.
Solution :
Question 12 .
Solution :
Question 13.
Solution :
Question 14.
Solution :
Question 15.
Solution :
Question 16.
Solution :
Question 17.
Solution :
Question18.
Solution :
Integrate the following functions in Exercises 19 to 23.
Question 19.
Solution :
Question 20.
Solution :
Question 21.
Solution :
Using equations (2) and (3) in (1), we obtain
Question 22.
Solution :
Question 23.
Solution :
Choose the correct answer in Exercise 24 and 25.
Question 24. equals
A. x tan−1 (x + 1) + C
B. tan− 1 (x + 1) + C
C. (x + 1) tan−1 x + C
D. tan−1 x + C
Solution :
Therefore, option (B) is correct.
Question 25. equals
Solution :
Therefore,option(B)iscorrect.
Exercise 7.5 Page: 258
Question 1.
Solution :
Question 2.
Solution :
Question 3.
Solution :
uestion 4.
Solution :
Question 5.
Solution :
Question 6.
Solution :
It can be seen that the given integrand is not a proper fraction.
Therefore, on dividing (1 − x2) by x(1 − 2x), we obtain
Question7.
Solution :
Question8.
Solution :
Question9.
Solution :
Question10.
Solution :
Question11.
Solution :
Question12.
Solution :
It can be seen that the given integrand is not a proper fraction.
Therefore, on dividing (x3 + x + 1) by x2 − 1, we obtain
Integrate the following function in Exercises 13 to 17.
Question13.
Solution :
Question 14.
Solution :
Question15.
Solution :
Question16. [Hint: multiply numerator and denominator by xn − 1 and put xn = t]
Solution :
Multiplying numerator and denominator by xn − 1, we obtain
Question17. [Hint: Put sin x = t]
Solution :
Integrate the following function in Exercises 18 to 21.
Question18.
Solution :
Equating the coefficients of x3, x2, x, and constant term, we obtain
A + C = 0
B + D = 4
4A + 3C = 0
4B + 3D = 10
On solving these equations, we obtain
A = 0, B = −2, C = 0, and D = 6
Question19.
Solution :
Question20.
Solution :
Multiplying numerator and denominator by x3, we obtain
Question21. [Hint: Put ex = t]
Solution :
Choose the correct answer in each of the Exercise 22 and 23.
Question22. equals:
Solution :
Therefore, option (B) is correct.
Question23. equals:
Solution :
Therefore, option (A) is correct.
Exercise 7.5 Page: 263
Question 1. x sin x
Solution : Let I = ∫ x sin x dx
Taking x as first function and sin x as second function and integrating by parts, we obtain
Question2. x sin3x
Solution :
Let I = ∫ x sin 3x dx
Taking x as first function and sin 3x as second function and integrating by parts, we obtain
Question3. x2 ex
Solution :
Let I = ∫ x2 ex dx
Taking x2 as first function and ex as second function and integrating by parts, we obtain
Again integrating by parts, we obtain
Question 4. x logx
Solution : Let I = ∫ x logx dx
Taking log x as first function and x as second function and integrating by parts, we obtain
Question 5. x log 2x
Solution : Let I = ∫ x log 2x dx
Taking log 2x as first function and x as second function and integrating by parts, we obtain
Question 6. x2 log x
Solution : Let I = ∫ x2 log x dx
Taking log x as first function and x2 as second function and integrating by parts, we obtain
Question7. xsin-1 x
Solution :
Let I = ∫ x sin-1 x
Taking sin-1 x as first function and x as second function and integrating by parts, we obtain
Question8. xtan-1 x
Solution :
Let I = ∫ x tan-1 x
Taking tan-1 x as first function and x as second function and integrating by parts, we obtain
Integrate the functions in Exercises 9 to 15.
Question 9. x cos-1 x
Solution :
Let I = ∫ x cos-1 x
Taking cos−1 x as first function and x as second function and integrating by parts, we obtain
Question10.
Solution :
Let I = ∫ .1 dx
Taking as first function and 1 as second function and integrating by parts, we obtain
Question11.
Solution :
Let
Taking cos−1 x as first function and as second function and integrating by parts, we obtain
Question12. xsec2 x
Solution : Let I = ∫ x sec2 x dx
Taking x as first function and sec2x as second function and integrating by parts, we obtain
Question 13. tan-1 x
Solution :
Let I = ∫ tan-1 x dx
Taking tan-1 x as first function and 1 as second function and integrating by parts, we obtain
Question14. x(logx)2
Solution :
Let I = ∫ x (log x)2 dx
Taking (log x)2 as first function and x as second function and integrating by parts, we obtain
Question 15. (x2 + 1) log x
Solution :
Integrate the functions in Exercises 16 to 22.
Question16.
Solution :
Question17.
Solution :
Question18.
Solution :
Question19.
Solution :
Question20.
Solution :
Question21.e2x sinx
Solution :
Let I = ∫ e2x sin x
Integrating by parts, we obtain
Question22.
Solution :
Choose the correct answer in Exercise 23 and 24.
Question23. equalsto
Solution :
LetI=
Therefore, option (A) is correct.
Question24. ∫equals:
(A) excosx+C
(B) ex secx+C
(C) ex sinx+C
(D) ex tanx+C
Solution :
Therefore, option (B) is correct.
Exercise 7.6 Page: 263
Question 1. x sin x
Solution : Let I = ∫ x sin x dx
Taking x as first function and sin x as second function and integrating by parts, we obtain
Question2. x sin3x
Solution :
Let I = ∫ x sin 3x dx
Taking x as first function and sin 3x as second function and integrating by parts, we obtain
Question3. x2 ex
Solution :
Let I = ∫ x2 ex dx
Taking x2 as first function and ex as second function and integrating by parts, we obtain
Again integrating by parts, we obtain
Question 4. x logx
Solution : Let I = ∫ x logx dx
Taking log x as first function and x as second function and integrating by parts, we obtain
Question 5. x log 2x
Solution : Let I = ∫ x log 2x dx
Taking log 2x as first function and x as second function and integrating by parts, we obtain
Question 6. x2 log x
Solution : Let I = ∫ x2 log x dx
Taking log x as first function and x2 as second function and integrating by parts, we obtain
Question7. xsin-1 x
Solution :
Let I = ∫ x sin-1 x
Taking sin-1 x as first function and x as second function and integrating by parts, we obtain
Question8. xtan-1 x
Solution :
Let I = ∫ x tan-1 x
Taking tan-1 x as first function and x as second function and integrating by parts, we obtain
Integrate the functions in Exercises 9 to 15.
Question 9. x cos-1 x
Solution :
Let I = ∫ x cos-1 x
Taking cos−1 x as first function and x as second function and integrating by parts, we obtain
Question10.
Solution :
Let I = ∫ .1 dx
Taking as first function and 1 as second function and integrating by parts, we obtain
Question11.
Solution :
Let
Taking cos−1 x as first function and as second function and integrating by parts, we obtain
Question12. xsec2 x
Solution : Let I = ∫ x sec2 x dx
Taking x as first function and sec2x as second function and integrating by parts, we obtain
Question 13. tan-1 x
Solution :
Let I = ∫ tan-1 x dx
Taking tan-1 x as first function and 1 as second function and integrating by parts, we obtain
Question14. x(logx)2
Solution :
Let I = ∫ x (log x)2 dx
Taking (log x)2 as first function and x as second function and integrating by parts, we obtain
Question 15. (x2 + 1) log x
Solution :
Integrate the functions in Exercises 16 to 22.
Question16.
Solution :
Question17.
Solution :
Question18.
Solution :
Question19.
Solution :
Question20.
Solution :
Question21.e2x sinx
Solution :
Let I = ∫ e2x sin x
Integrating by parts, we obtain
Question22.
Solution :
Choose the correct answer in Exercise 23 and 24.
Question23. equalsto
Solution :
LetI=
Therefore,option,(A)iscorrect.
Question24. ∫equals:
(A) excosx+C
(B) ex secx+C
(C) ex sinx+C
(D) ex tanx+C
Solution :
Therefore, option (B) is correct.
Exercise 7.7 Page: 266
Question 1.
Solution :
Question 2.
Solution :
Question 3.
Solution :
Question 4.
Solution :
Question 5.
Solution :
Question 6.
Solution :
Question 7.
Solution :
Question 8.
Solution :
Question 9.
Solution :
Choose the correct answer in Exercise 10 to 11.
Question10. is equal to:
Solution :
Therefore, option (A) is correct.
Question 11. is equal to:
Therefore, option (D) is correct.
Exercise 7.8 Page: 270
Question 1.
Solution :
It is know that
Question 2.
Solution :
Let I =
It is know that
Question 3.
Solution :
We know that
Question 4.
Solution :
We know that
From equations (2) and (3), we obtain
Question 5.
Solution: LetI=
We know that
Question 6.
Solution :
We know that
Exercise 7.9 Page: 273
Evaluate the definite integrals in Exercises 1 to 11.
Question1.
Solution :
By second fundamental theorem of calculus, we obtain
Question2.
Solution :
By second fundamental theorem of calculus, we obtain
I = F(3) – F(2)
= log|3| – log|2| = log 3/2
Question3.
Solution :
By second fundamental theorem of calculus, we obtain
Question4.
Solution :
By second fundamental theorem of calculus, we obtain
Question5.
Solution :
By second fundamental theorem of calculus, we obtain
Question6.
Solution :
By second fundamental theorem of calculus, we obtain
Question7.
Solution :
By second fundamental theorem of calculus, we obtain
Question8.
Solution :
By second fundamental theorem of calculus, we obtain
Question9.
Solution :
By second fundamental theorem of calculus, we obtain
Question10.
Solution :
By second fundamental theorem of calculus, we obtain
Question11.
Solution :
By second fundamental theorem of calculus, we obtain
Evaluate the definite integrals in Exercises 12 to 20.
Question12.
Solution :
By second fundamental theorem of calculus, we obtain
Question13.
Solution :
By second fundamental theorem of calculus, we obtain
Question14.
Solution :
Question15.
Solution :
By second fundamental theorem of calculus, we obtain
Question16.
Solution :
Equating the coefficients of x and constant term, we obtain
Question17.
Solution :
By second fundamental theorem of calculus, we obtain
Question18.
Solution :
By second fundamental theorem of calculus, we obtain
I = F(π) – F(0)
= sin π – sin 0
= 0
Question19.
Solution :
By second fundamental theorem of calculus, we obtain
Question20.
Solution :
By second fundamental theorem of calculus, we obtain
Choose the correct answer in Exercises 21 and 22.
Question21. equals:
(A)π/3
(B)2π/3
(C)π/6
(D)π/12
Solution :
Therefore, option (D) is correct.
Question22. equals:
(A)π/6
(B)π/12
(C)π/24
(D)π/4
Solution :
By second fundamental theorem of calculus, we obtain
Therefore, option (C) is correct.
Exercise 7.10 Page: 280
Question:1 By using the properties of definite integrals, evaluate the integrals in Exercises 1 to 19.
Answer:
We have ............................................................. (i)
By using
We get :-
or
................................................................ (ii)
Adding both (i) and (ii), we get :-
or
or
or
or
Question:2 By using the properties of definite integrals, evaluate the integrals in Exercises 1 to 19.
Answer:
We have .......................................................................... (i)
By using ,
We get,
or .......................................................(ii)
Adding (i) and (ii), we get,
or
or
Thus
Question:3 By using the properties of definite integrals, evaluate the integrals in Exercises 1 to 19.
Answer:
We have ..................................................................(i)
By using :
We get,
or . ............................................................(ii)
Adding (i) and (ii), we get :
or
or
Thus
Question:4 By using the properties of definite integrals, evaluate the integrals in Exercises 1 to 19.
Answer:
We have ..................................................................(i)
By using :
We get,
or . ............................................................(ii)
Adding (i) and (ii), we get :
or
or
Thus
Question:5 By using the properties of definite integrals, evaluate the integrals in Exercises 1 to 19.
Answer:
We have,
For opening the modulas we need to define the bracket :
If (x + 2) < 0 then x belongs to (-5, -2). And if (x + 2) > 0 then x belongs to (-2, 5).
So the integral becomes :-
or
This gives
Question:6 By using the properties of definite integrals, evaluate the integrals in Exercises 1 to 19.
Answer:
We have,
For opening the modulas we need to define the bracket :
If (x - 5) < 0 then x belongs to (2, 5). And if (x - 5) > 0 then x belongs to (5, 8).
So the integral becomes:-
or
This gives
Question:7 By using the properties of definite integrals, evaluate the integrals in Exercises 1 to 19.
Answer:
We have
U sing the property : -
We get : -
or
or
or
or
or
Question:8 By using the properties of definite integrals, evaluate the integrals in Exercises 1 to 19.
Answer:
We have
By using the identity
We get,
or
or
or
or
or
or
Question:9 By using the properties of definite integrals, evaluate the integrals in Exercises 1 to 19.
Answer:
We have
By using the identity
We get :
or
or
or
or
or
Question:10 By using the properties of definite integrals, evaluate the integrals in Exercises 1 to 19.
Answer:
We have
or
or ..............................................................(i)
By using the identity :
We get :
or ....................................................................(ii)
Adding (i) and (ii) we get :-
or
or
Question:11 By using the properties of definite integrals, evaluate the integrals in Exercises 1 to 19.
Answer:
We have
We know that sin 2 x is an even function. i.e., sin 2 (-x) = (-sinx) 2 = sin 2 x.
Also,
So,
or
or
Question:12 By using the properties of definite integrals, evaluate the integrals in Exercises 1 to 19.
Answer:
We have ..........................................................................(i)
By using the identity :-
We get,
or ............................................................................(ii)
Adding both (i) and (ii) we get,
or
or
or
Question:13 By using the properties of definite integrals, evaluate the integrals in Exercises 1 to 19.
Answer:
We have
We know that is an odd function.
So the following property holds here:-
Hence
Question:14 By using the properties of definite integrals, evaluate the integrals in Exercises 1 to 19.
Answer:
We have
I t is known that :-
If f (2a - x) = f(x)
If f (2a - x) = - f(x)
Now, using the above property
Therefore,
Question:15 By using the properties of definite integrals, evaluate the integrals in Exercises 1 to 19.
Answer:
We have ................................................................(i)
By using the property :-
We get ,
or ......................................................................(ii)
Adding both (i) and (ii), we get
Thus I = 0
Question:16 By using the properties of definite integrals, evaluate the integrals in Exercises 1 to 19.
Answer:
We have .....................................................................................(i)
By using the property:-
We get,
or
....................................................................(ii)
Adding both (i) and (ii) we get,
or
or
or ........................................................................(iii)
or ........................................................................(iv)
or .....................................................................(v)
Adding (iv) and (v) we get,
Question:17 By using the properties of definite integrals, evaluate the integrals in Exercises 1 to 19.
Answer:
We have ................................................................................(i)
By using, we get
We get,
.................................................................(ii)
Adding (i) and (ii) we get :
or
or
Question:18 By using the properties of definite integrals, evaluate the integrals in Exercises 1 to 19.
Answer:
We have,
For opening the modulas we need to define the bracket :
If (x - 1) < 0 then x belongs to (0, 1). And if (x - 1) > 0 then x belongs to (1, 4).
So the integral becomes:-
or
This gives
Question:19 Show that if and are defined as and
Answer:
Let ........................................................(i)
This can also be written as :
or ................................................................(ii)
Adding (i) and (ii), we get,
or
Question:20 Choose the correct answer in Exercises 20 and 21.
The value of is is
(A) 0
(B) 2
(C)
(D) 1
Answer:
We have
This can be written as :
Also if a function is even function then
And if the function is an odd function then :
Using the above property I become:-
or
or
Question:21 Choose the correct answer in Exercises 20 and 21.
The value of is
Answer:
We have
.................................................................................(i)
By using :
We get,
or .............................................................................(ii)
Adding (i) and (ii), we get:
or
Thus
Chapter 7 Miscellaneous Exercise
NCERT Solutions for Class 12 Maths Chapter 7 Miscellaneous Exercise
Question 1:
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Question 2:
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Question 3:
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