Evaluate: `int1/((x+1)sqrt(x^2-1))dx`

Explanation

`x+1=1/t`

`dx=(-1/t^2)dt`

`int frac{(-1/t^2)}{1/t sqrt((1/t -1)^2-1)}dt`

`=- int frac{dt}{sqrt(1-2t)}`

`1-2t=m=>dt=(dm)/-2`

`int frac{dm}{2 sqrt m}`

`=1/2 xx 2 sqrtm+C`

`=sqrt(1-2t)+C`
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