integral of (x^2)rt(x^2-1)dx using the substitution x=sec(theta)?

Question

I = ∫ x² (x² - 1)^(1/2) dx
this is what it is...

Answer 1

Assuming question shold read as:-
I = ∫ 1 / [ x² (x² - 1)^(1/2) ] dx
Let x = sec θ
dx = sec θ tan θ
I = ∫ [(sec θ tan θ) / (sec² θ (sec² θ - 1)^(1/2)] dθ
I = ∫ [(tan θ) / (sec θ tan θ) ] dθ
I = ∫ cos θ dθ
I = sin θ + C

Answer 2

∫1/(x√(x² - 1) = sec x + C

Answer 3

Whats wrong wtih this picture, nobody knows what the hell is going on