Easier said than done (Dark)

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In this video we will solve the integral given in thumbnail.
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[@gd_fallen2986]

This one ia pretty easy, use u-sub. X=√sec(u), x^4=sec^2(u), dx = sec(u)tan(u)/2√sec(u)
After using the trig idenity of sec^2(x)-1 = tanx, all terms cancel out leaving you with the integral of 1/2 du. This is simply u/2. We know x^2 = sec(u), so u = sec^-1(x^2). Now all we have to do is evlauate this from infinity to 1. The easist way to do this is to change it to cos^-1(1/x^2) and then we can evaluate it simply. So we get (cos^-1(1/infinity) - cos^-1(1/1))/2 = (cos^-1(0) - cos^-1(1))/2 = (pi/2 - 0)/2 = pi/4.

[@dhruvchaudhary5379]

This can be re written as 1/((x^3)sqrt( 1-(1/x)^2)). Take 1/X^2 as t