MCQ
The solution of the equation $4{\cos ^2}x + 6$${\sin ^2}x = 5$
  • A
    $x = n\pi \pm \frac{\pi }{2}$
  • $x = n\pi \pm \frac{\pi }{4}$
  • C
    $x = n\pi \pm \frac{{3\pi }}{2}$
  • D
    None of these

Answer

Correct option: B.
$x = n\pi \pm \frac{\pi }{4}$
b
(b) $4 + 2{\sin ^2}x = 5$

$ \Rightarrow $ ${\sin ^2}x = \frac{1}{2} = {\sin ^2}\frac{\pi }{4}$

$\Rightarrow x = n\pi \pm \frac{\pi }{4}$.

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