سیگما

`Q=int(dx)/((x+1)^5sqrt(x^2+2x))`
`1/t=x+1`
`x=1/t-1`
`(dx)/(dt)=-1/(t^2)`
`Q=int (-1/(t^2))/((1/t)^5 sqrt((1/t-1)^2+2(1/t-1))) dt`
`Q=-int (t^3)/(sqrt((1/t)^2-1)) dt`
`Q=int (-t^4)/sqrt(1-t^2) dt`
`Q=(At^3+Bt^2+Ct+D)sqrt(1-t^2)+ K int 1/(sqrt(1-t^2)) dt`
`A=1/4,B=0,C=3/8,D=0,K=-3/8`
`Q=(1/4t^3+3/8t)sqrt(1-t^2)-3/8arcsin(t)`
`Q=1/8(t(2t^2+3)sqrt(1-t^2)-3arcsint)`
`|t=(1/(x+1))`