Integrate the following functions `sqrt(1-4x-x^2)`

Explanation

`int sqrt(1-4x-x^2) dx`
=`int sqrt(1-(x^2+4x))dx`
=`int sqrt(1-(x^2+4x+4-4) dx`
=`int sqrt(1-(x+2)^2+4) DX`
=`int sqrt((sqrt5)^2-(x+2)^2) dx`
`(x+2)/2 sqrt((sqrt)^2-(x+2)^2) + (sqrt5)^2/2 sin^-1((x+2)/sqrt5) +c`
`(x+2)/2 sqrt(1-4x-x^2)+ 5/2 sin^-1((x+2)/sqrt5)+c`