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Trigonometrical Equations
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Number of solutions of equation $secx = 1 + cosx + cos^2x + ........ \infty$ in $x \in [-50 \pi, 50 \pi]$ is -
A
$96$
B
$99$
C
$100$
D
$101$
Solution
$\sec x=\frac{1}{1-\cos x} \Rightarrow \cos x=1-\cos x$
$\Rightarrow \cos x=\frac{1}{2}$
2 solutions in $[0,2 \pi]$
$\therefore 100$ solutions.
Standard 11
Mathematics