Hard INTEGER +4 / -1 PYQ · JEE Mains 2024

Let $f: \mathbb{R} \rightarrow \mathbb{R}$ be a function defined by $f(x)=\frac{4^x}{4^x+2}$ and $$M=\int_\limits{f(a)}^{f(1-a)} x \sin ^4(x(1-x)) d x, N=\int_\limits{f(a)}^{f(1-a)} \sin ^4(x(1-x)) d x ; a \neq \frac{1}{2}$$. If $\alpha M=\beta N, \alpha, \beta \in \mathbb{N}$, then the least value of $\alpha^2+\beta^2$ is equal to __________.

Answer (integer) 5

Solution

<p>$\mathrm{f}(\mathrm{a})+\mathrm{f}(1-\mathrm{a})=1$</p> <p>$M=\int_\limits{f(a)}^{f(1-a)}(1-x) \cdot \sin ^4 x(1-x) d x$</p> <p>$\mathrm{M}=\mathrm{N}-\mathrm{M} \qquad 2 \mathrm{M}=\mathrm{N}$</p> <p>$\alpha=2 ; \beta=1 \text {; }$</p> <p>Ans. 5</p>

About this question

Subject: Mathematics · Chapter: Definite Integration · Topic: Properties of Definite Integrals

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