最佳答案:I = (1/4)∫(1-cos2t)^2dt - ∫[1-(cost)^2]^2dcost= (1/4)∫[3/2-2cos2t+(1/2)cos4t]dt-
最佳答案:要求∫_0^2pi▒〖(sin⁡(t/2)⁡ )^5〗dt,先化sin(t/2)的四次方,(sin(t/2))^4=(1-(cos(t/2))^2)^2=1-2