方法如下，请作参考：
∫dx/[√(x+3)+√(x-1)]=∫ [√(x+3)-√(x-1)]/[(x+3)-(x-1)] dx=(1/4)∫ [√(x+3)-√(x-1) ] dx=(1/6)[ (x+3)^(3/2) +(x-1)^(3/2)] + C
