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$\frac{1}{\cos x} - \cos x = \sin x * \tan x$

I have tried a few things and nothing works

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Left Side

$\frac{1}{\cos x} - \cos x$

$1 - (\cos x)^2$

$1 - 1 + \frac{\cos 2x}{2}$

$ \frac{\cos 2x}{2}$

$ \frac{\cos x}{2} \times \frac{\cos}{2}$

... And I am out in left field!

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1 Answer

$\begingroup$

$$\frac{1}{\cos x} - \cos x = \frac{1- \cos^2 x}{\cos x}$$

Now I think you can finish.

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