Posted by **krista** on Thursday, May 6, 2010 at 11:12pm.

show that: (1-tanx)/(1+tanx)= (1-sinx)/(cos2x)

- Precal -
**drwls**, Friday, May 7, 2010 at 6:32am
Is the denominator on the right cos(2x) or cos^2x ? Neither seems to work.

If x = pi/4, the left side is 0 and the right side is 0.293/0 = infinity, if the denominator is cos 2x.

Therefore what you wrote is not an identity.

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