$\displaystyle \int\frac{dx}{x\sqrt{x^2-1}}$
using substitution $\displaystyle x=\frac{1}{t}$ in order to find integral
i got that $\displaystyle dx=-\frac{dt}{t^2}$
if i substitute it what should i do with denominator, especially with sqrt ?
oh i hate it. i am going to have a test tomorrow