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Trigonometrical Equations
easy
જો $5{\cos ^2}\theta + 7{\sin ^2}\theta - 6 = 0$, તો $\theta $ ની વ્યાપક કિમત મેળવો.
A
$2n\pi \pm \frac{\pi }{4}$
B
$n\pi \pm \frac{\pi }{4}$
C
$n\pi + {( - 1)^n}\frac{\pi }{4}$
D
એકપણ નહીં.
Solution
(b) $5 – 5{\sin ^2}\theta + 7{\sin ^2}\theta = 6$
$ \Rightarrow $ $2{\sin ^2}\theta = 1$
$ \Rightarrow $ ${\sin ^2}\theta = \frac{1}{2} = {\sin ^2}\left( {\frac{\pi }{4}} \right) $
$\Rightarrow \theta = n\pi \pm \frac{\pi }{4}$.
Standard 11
Mathematics
