Evaluate: `intx/((x^2+4)sqrt(x^2+1))\ dx`

Explanation

Let, `x^2+1=t^2`

`x^2+4=t^2+3`

`xdx=tdt`


`=intx/((x^2+4)sqrt(x^2+1))\ dx`


`=int(tdt)/((t^2+3)t)`


`=int(dt)/((t^2+3))`


We know that,


`int(dz)/((z^2+a^2))=(1)/(a)tan^(-1) ((z)/(a))+C`


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