∫<0,1>[x/(1+x²)]dx
=(1/2)∫<0,1>[1/(1+x²)]d(1+x²)
=(1/2)ln(1+x²)|<0,1>
=(1/2)ln2
∫<0,1>√(1+√x)dx
令√(1+√x)=t,则1+√x=t² ==> √x=t²-1 ==> x=(t²-1)² ==> dx=2(t²-1)*2tdt
且,x=0时,t=1;x=1时,t=√2
原式=∫<1,√2>t*4t(t²-1)dt
=4∫<1,√2>(t^4-t²)dt
=(4/5)t^5-(4/3)t³|<1,√2>
=(8√2-7)/15