Q99 / 160 · AP EAMCET 2020 (17 Sep Shift 2) · Mathematics
\(\int_{-\pi / 4}^{\pi / 4} x^3 \sin ^4(x) d x=\)
- Correct answerA0
- B\(\pi\)
- C1
- D\(2 \pi\)
Solution
\(I=\int_{-\pi / 4}^{\pi / 4} x^3 \cdot \sin ^4 x d x\)
As, \(\int_{-a}^a f(x) d x=0\), when
\(f(-x)=-f(x),\)
We have,
\(\begin{gathered}
f(-x)=(-x)^3 \sin ^4(-x) \\
=-\left(x^3 \cdot \sin ^4 x\right)=-f(x) \\
\therefore \quad \int_{-\pi / 4}^{\pi / 4} x^3 \cdot \sin ^4 x \cdot d x=0 .
\end{gathered}\)
Hence, the correct answer is option: 'A'.