Question Details

Match List-I with List-II


             List-I (Definite integral) List-II (Value)
             (A) 0 1 2x /1 + x2  dx (I) 2
(B) ∫ 1 1 sin 3 x cos 4 x d x (II) loge ( 32 )
             (C) 0 π sinx dx (III) loge 2
             (D) 2 3 2 x2 - 1 dx (IV) 0

Choose the correct answer from the options given below:

Options

A

(A) - (I), (B) - (II), (C) - (III), (D) - (IV)

B

(A) - (III), (B) - (II), (C) - (I), (D) - (IV)

C

(A) - (III), (B) - (I), (C) - (IV), (D) - (II)

D

(A) - (III), (B) - (IV), (C) - (I), (D) - (II)

Show Answer

Correct Answer :

Option D

(A) - (III), (B) - (IV), (C) - (I), (D) - (II)

Solution :

The correct option is (A) - (III), (B) - (IV), (C) - (I), (D) - (II).

Let us evaluate each definite integral in List-I step-by-step to find its corresponding value in List-II.

1. Evaluation of Integral (A):
The integral is:
I = 0 1 2 x 1 + x 2 d x
To solve this, we can use the method of substitution. Let:
u = 1 + x 2
Differentiating both sides with respect to x gives:
d u = 2 x d x
Next, we determine the new limits of integration:
When x=0, u=1+02=1.
When x=1, u=1+12=2.
Substituting these values into the integral, we get:
I = 1 2 1 u d u
Integrating 1u yields:
I = [ log e u ] 1 2 = log e 2 - log e 1
Since loge1=0, we have:
I = log e 2
Thus, (A) matches with (III).

2. Evaluation of Integral (B):
The integral is:
I = - 1 1 sin 3 x cos 4 x d x
Let us analyze the integrand function:
f ( x ) = sin 3 x cos 4 x
We test whether f(x) is an odd or even function by replacing x with -x:
f ( - x ) = ( sin ( - x ) ) 3 ( cos ( - x ) ) 4
Since sin(-x)=-sinx and cos(-x)=cosx, we obtain:
f ( - x ) = ( - sin x ) 3 ( cos x ) 4 = - sin 3 x cos 4 x = - f ( x )
Because f(-x)=-f(x), the integrand is an odd function.
By the properties of definite integrals, any integral of an odd function over symmetric limits [-a,a] is zero:
- a a f ( x ) d x = 0
Therefore:
I = 0
Thus, (B) matches with (IV).

3. Evaluation of Integral (C):
The integral is:
I = 0 π sin x d x
Evaluating the antiderivative of sinx gives:
I = [ - cos x ] 0 π = - cos π - ( - cos 0 )
Knowing that cosπ=-1 and cos0=1, we compute:
I = - ( - 1 ) + 1 = 1 + 1 = 2
Thus, (C) matches with (I).

4. Evaluation of Integral (D):
The integral is:
I = 2 3 2 x 2 - 1 d x
We use the standard integration formula:
1 x 2 - a 2 d x = 1 2 a log e | x - a x + a |
Setting a=1, our integral becomes:
I = 2 [ 1 2 log e | x - 1 x + 1 | ] 2 3 = [ log e | x - 1 x + 1 | ] 2 3
Now we apply the limits of integration:
I = log e ( 3 - 1 3 + 1 ) - log e ( 2 - 1 2 + 1 )
Simplifying the fractions:
I = log e ( 2 4 ) - log e ( 1 3 ) = log e ( 1 2 ) - log e ( 1 3 )
Using the logarithmic property logA-logB=log(AB):
I = log e ( 1 / 2 1 / 3 ) = log e ( 3 2 )
Thus, (D) matches with (II).

Conclusion:
By matching all items, we obtain:
(A) - (III), (B) - (IV), (C) - (I), (D) - (II).

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