What is the integral from 0 to 1 of x*sqrt(x^2+8)xx2+8?

1 Answer
May 6, 2015

Try this:
intxsqrt(x^2+8)dx=xx2+8dx=
But d[x^2+8]=2xdxd[x2+8]=2xdx
So:
1/2intsqrt(x^2+8)d[x^2+8]=12x2+8d[x2+8]=
=1/2int(x^2+8)^(1/2)d[x^2+8]=1/2((x^2+8)^(3/2))/(3/2)=12(x2+8)12d[x2+8]=12(x2+8)3232
Between 00 and 11:
=1/3(x^2+8)^(3/2)|_0^1=13(x2+8)3210=9-8/3sqrt(8)=9-16/3sqrt(2)9838=91632