All the pairs $(x, y)$ that satisfy the inequality $2^{\sqrt{\sin ^2 x-2 \sin x+5}}, \frac{1}{4\sin ^2 y}…
All the pairs $(x, y)$ that satisfy the inequality $2^{\sqrt{\sin ^2 x-2 \sin x+5}}, \frac{1}{4\sin ^2 y} \leq 1$ also satisfy the equation
- $2|\sin x|=\sin y$
- $2 \sin x=\sin y$
- $\sin x=2 \sin y$
- $\sin x=|\sin y|$
Solution
$2^{\sqrt{\sin ^2 x-2 \sin x+5}} \cdot 2^{-2 \sin ^2 y} \leq 1$
$\begin{aligned} & 2^{\sqrt{\sin ^2 x-2 \sin x+5}} \leq 2^{2 \sin ^2 y} \\ & \sqrt{\sin ^2 x-2 \sin x+5} \leq 2 \sin ^2 y \\ & \sqrt{(\sin x-1)^2+4} \leq 2 \sin ^2 y\end{aligned}$
$\begin{aligned} & (\sin x-1)^2+4 \leq 4 \sin ^4 y \\ & -1 \leq \sin y \leq 1 \\ & 0 \leq \sin ^4 y \leq 1 \\ & \text { For } \sin y= \pm 1 \text { (maximum value) } \\ & (\sin x-1)^2+4=4\end{aligned}$
$\begin{aligned} & (\sin x-1)^2=0 \\ & \sin x=1 \\ & \sin x=|\sin y|\end{aligned}$
Asked in: AP EAMCET 2022 (05 Jul Shift 2)
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