The value of $f(\mathrm{l})$, given the equation $\int_0^{x^2} x f(t) d t=x^5-x^3$ is
The value of $f(\mathrm{l})$, given the equation $\int_0^{x^2} x f(t) d t=x^5-x^3$ is
- 4
- 3
- 2
- 1
Solution
$\int_0^{x^2} x \cdot f(t) d t=x^5-x^3$
Differentiate w.r.t. $x$ on both sides,
$
\begin{aligned}
x^2 \cdot f\left(x^2\right) \cdot \frac{d}{d x} x^2-0 & =5 x^4-3 x^2 \\
x^2 f\left(x^2\right)(2 x) & =5 x^4-3 x^2
\end{aligned}
$
$
2 x^3 f\left(x^2\right)=5 x^4-3 x^2
$
Put $x=1$
$
2 \cdot 1 \cdot f(1)=5(1)-3(1) \quad \Rightarrow f(1)=1
$
Hence, option (4) is correct
Asked in: AP EAMCET 2020 (22 Sep Shift 2)
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