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3.Trigonometrical Ratios, Functions and Identities
easy
જો $\sin x + \cos x = \frac{1}{5},$ તો $\tan 2x = . . .$
A
$\frac{{25}}{{17}}$
B
$\frac{{7}}{{25}}$
C
$\frac{{25}}{7}$
D
$\frac{{24}}{7}$
Solution
(d) $\sin x + \cos x = \frac{1}{5}$
==> ${\sin ^2}x + {\cos ^2}x + 2\sin x\cos x = \frac{1}{{25}}$
$\sin 2x = \frac{{ – 24}}{{25}}$
==> $\cos 2x = \frac{{ – 7}}{{25}}$
==> $\tan 2x = \frac{{24}}{7}$.
Standard 11
Mathematics