Question

plse help me to solve this

Answer 1

I can't help solve it but here are some alternate forms of 1+2tan^x from wolfram alpha:
(sin^2(x)+1) sec^2(x)
-1/2 (cos(2 x)-3) sec^2(x)
1/2 (3 sec^2(x)-cos(2 x) sec^2(x))
here's the website with more info:
http://www.wolframalpha.com/input/?i=1%2B2+tan%5E2x

Answer 2

\[1+2 \cos 2\theta=1+2\frac{ 1-\tan ^{2}\theta }{1+\tan ^{2}\theta }\]
substitute the value of \[\tan ^{2}\theta \]
and simplify.