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Match List-I with List-II

List-IList-II
IntegralValue
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(A) ∫−11(∣x∣+1)dx\int_{-1}^{1} (\vert x\vert + 1) dx(I) 0
(B) ∫−22∣x+1∣dx\int_{-2}^{2} \vert x + 1\vert dx(II) 2
(C) ∫−113∣x2∣dx\int_{-1}^{1} 3\vert x^2\vert dx(III) 5
(D) ∫−11x∣x∣dx\int_{-1}^{1} x\vert x\vert dx(IV) 3

Choose the correct answer from the options given below:

Solution

✅ Correct Option: 4

(A) ∫−11(∣x∣+1) dx\int_{-1}^{1} (|x| + 1)\, dx

Since ∣x∣|x| is an even function, ∫−aaf(x) dx=2∫0af(x) dx\int_{-a}^{a} f(x)\,dx = 2\int_{0}^{a} f(x)\,dx

=2∫01(x+1) dx= 2\int_{0}^{1} (x + 1)\, dx

=2[x22+x]01= 2\left[\dfrac{x^2}{2} + x\right]_0^1

=2(12+1)= 2\left(\dfrac{1}{2} + 1\right)

=2×32=3⟶(IV)= 2 \times \dfrac{3}{2} = 3 \longrightarrow \text{(IV)}


(B) ∫−22∣x+1∣ dx\int_{-2}^{2} |x + 1|\, dx

∣x+1∣=0|x + 1| = 0 when x=−1x = -1, so splitting at x=−1x = -1:

For x<−1x < -1, ∣x+1∣=−(x+1)|x+1| = -(x+1)

For x≥−1x \geq -1, ∣x+1∣=(x+1)|x+1| = (x+1)

=∫−2−1−(x+1) dx+∫−12(x+1) dx= \int_{-2}^{-1} -(x+1)\, dx + \int_{-1}^{2} (x+1)\, dx

First integral:

=[−x22−x]−2−1= \left[-\dfrac{x^2}{2} - x\right]_{-2}^{-1}

=(−12+1)−(−2+2)=12= \left(-\dfrac{1}{2} + 1\right) - \left(-2 + 2\right) = \dfrac{1}{2}

Second integral:

=[x22+x]−12= \left[\dfrac{x^2}{2} + x\right]_{-1}^{2}

=(2+2)−(12−1)=4+12=92= \left(2 + 2\right) - \left(\dfrac{1}{2} - 1\right) = 4 + \dfrac{1}{2} = \dfrac{9}{2}

=12+92=5⟶(III)= \dfrac{1}{2} + \dfrac{9}{2} = 5 \longrightarrow \text{(III)}


(C) ∫−113∣x2∣ dx\int_{-1}^{1} 3|x^2|\, dx

Since x2≥0x^2 \geq 0 always, ∣x2∣=x2|x^2| = x^2. Also x2x^2 is an even function.

=3×2∫01x2 dx= 3 \times 2\int_{0}^{1} x^2\, dx

=6[x33]01= 6\left[\dfrac{x^3}{3}\right]_0^1

=6×13=2⟶(II)= 6 \times \dfrac{1}{3} = 2 \longrightarrow \text{(II)}


(D) ∫−11x∣x∣ dx\int_{-1}^{1} x|x|\, dx

f(−x)=(−x)∣−x∣=−x∣x∣=−f(x)f(-x) = (-x)|-x| = -x|x| = -f(x)

Since f(x)=x∣x∣f(x) = x|x| is an odd function, ∫−aaf(x) dx=0\int_{-a}^{a} f(x)\, dx = 0

=0⟶(I)= 0 \longrightarrow \text{(I)}


(A) →\rightarrow (IV), (B) →\rightarrow (III), (C) →\rightarrow (II), (D) →\rightarrow (I)

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