Having troubles proving the identity tanx/secx+1 = 2cosx-2cosx^2x/sin2x Thanks
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What have you tried? Does this help? $\displaystyle \frac{\tan x}{\sec x+1}\times \frac{\sec x-1}{\sec x-1}= \frac{\tan x (\sec x-1)}{\sec^2 x-1}= \frac{\tan x (\sec x-1)}{\tan^2 x}$
still having troubles
Now, does this help? $\displaystyle \frac{\tan x (\sec x-1)}{\tan^2 x} = \frac{\cos x(\sec x-1)}{\sin x} = \frac{2\cos^2 x(\sec x-1)}{2\cos x \sin x} = \frac{2\cos^2 x\sec x - 2\cos^2 x}{\sin 2x}$
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