∫(4x^3-x^4)^(1/2)dx 积分限2,0=∫x[(4x-x^2)^(1/2)]dx=∫x[(4-(x-2)^2]^(1/2)]dxx-2=t=∫(t+2)[(4-t^2]^(1/2)]dt 积分限0,-2=∫t[(4-t^2]^(1/2)]dt+∫2[(4-t^2]^(1/2)]dt 积分限0,-2第一部分好求,第二部分麻烦,用t...