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February 13, 2016
Posted by **Jack** on Thursday, December 19, 2013 at 3:50pm.

- Pre-Calc -
**Steve**, Thursday, December 19, 2013 at 3:54pmI assume you mean

(2-sec^2 x)/(1+tan^2 x)

since sec^2 x = 1+tan^2 x, we have

(1-tan^2 x)/(sec^2 x)

multiply top and bottom by cos^2 x

= (cos^2 x - sin^2 x)/1

= cos(2x)