1.cosx=1-x^2/2+(x^4)/24
e^(-x^2/2)=1-x^2/2+(x^2/2)^2/2
ln(1-x)=-x-x^2/2
带入可得
(-x^4/12)/(-x^4/2)
=1/6
2.对右边求导
=-cosx+xsinx+cosx+0
=xsinx=左边的积分项
所以积分成立
1.cosx=1-x^2/2+(x^4)/24
e^(-x^2/2)=1-x^2/2+(x^2/2)^2/2
ln(1-x)=-x-x^2/2
带入可得
(-x^4/12)/(-x^4/2)
=1/6
2.对右边求导
=-cosx+xsinx+cosx+0
=xsinx=左边的积分项
所以积分成立