Question

integral of sqrt(1+cos2x)dx

Answer 1

\[\int\limits \sqrt{\left( 1+\cos 2x \right)}dx=\int\limits \sqrt{2\cos ^2x}~dx=\sqrt{2}\int\limits \cos x~dx+c\]
=?

Answer 2

@surjithayer where did the one go then when you substituted the 2cos^2x in for cos2x?

Answer 3

It's an identity, @professional_loser_ ^_^
\[\Large 1 = \cos^2(x) + \sin^2(x)\]\[\Large \cos(2x) = \cos^2(x) - \sin^2(x)\]
And just add up these two equations :D

Answer 4

thank you! I completely blanked on that identity, lol. @terenzreignz