【高数】问一道积分题(点击大图可放大)
2个回答

(1/2)∫根号(原式)dx^2=(1/2)∫根号((1-x)/(1+x))dx

=(1/2)∫根号((1-x^2)/(1+x)^2)dx

=(1/2)∫根号(1-x^2)/(1+x)dx

令x=sin(x)

=(1/2)∫cos(x)^2/(1+sin(x)dx

=(1/2)∫(1-sin(x)^2)/(1+sin(x))dx

=(1/2)∫1-sin(x)dx

=(1/2)[x+cox(x)](上限为π/2,下限为0)=π/4-1/2