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4 votes
How do I solve cos x> 1/2 sin x?

User Pery Mimon
by
6.5k points

1 Answer

4 votes

Divide both sides by
\frac12\cos x:


(\cos x)/(\frac12\cos x)>(\frac12\sin x)/(\frac12\cos x)\implies2>(\sin x)/(\cos x)=\tan x

If
-\frac\pi2<x<\frac\pi2, then


\tan x<2\implies-\frac\pi2<x<\tan^(-1)2

and more generally, for any integer
n,


n\pi-\frac\pi2<x<n\pi+\tan^(-1)2

User Foogry
by
6.0k points