integral sec^4 (x/2) dx from 0 to pi/2
you deleted the older post..
\[\int\limits_{?}^{?}\sec^4(\frac{x}{2})dx\]
sec^2 * sec^2(x) and change one into tangent
or tan i mean
then you will have a derivative and it's function
anyway apply integration by parts and simplify\[I = 2\sec^2(x/2) \tan(x/2) - 4I + 4\int\limits\limits_{}^{} \tan(x/2) \sec^2(2x/2)dx\] to get
\[\cos^2+\sin^2=1\] \[1+\tan^2=\sec^2\]
eww that is ugly...
\[5I = 2\sec^2(x/2) \tan(x/2)+ 8\sec^2(x/2)\] on applying limits we get -3/5
sec^4(x/2) dx u=x/2 du=1/2 dx 2du=dx 2/cos^4 (u) du
double susdtitution
you could do double substitution but i still believe splitting the sec up and then creating two integrals from that
ok
like this\[\int\limits_{?}^{?}\tan^2(x/2)\sec^2(x)dx +\int\limits_{?}^{?}\sec^2(x)dx\]
i mean x/2 for the other one
u = tan(x/2) du = 1/2(sec^2(x/2)dx
2du=sec^2(x/2)dx and then you have just integral of u^2
the second one you can just take the integral it will just be tan(x/2)
or double substitution.,..... but parts seems a little insane. it'd work but that would be a lot of evaluating
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