Question

Please help :)

Answer 1

http://screencast.com/t/MOG0Zess1kQ

Answer 2

@Hero @ash2326 @AllTehMaffs

Answer 3

use a trig sub

Answer 4

ok

Answer 5

notice:

\[\sin(\theta) = \frac{ x }{ \sqrt{1+x^2} }\]
and

\[\tan(\theta) = x\]
so dx = \[\sec^2(\theta) d \theta\]

so substitute everything in

Answer 6

actually i give you a better subsitution

\[\cos(\theta) = \frac{ 1 }{ \sqrt{1+x^2 } } \]
so
\[\sec(\theta) = \sqrt{1+x^2} \]
so
\[\sec^4(\theta) = (1+x^2)^2 \]

Answer 7

theres your new integral
\[\int\limits_{}^{} \frac{ 1 - \tan^2(\theta) }{ \sec^4(\theta) } \sec^2(\theta) d \theta \]

simplify this