用凑微分法求∫cos2xdx

2025-01-07 01:51:33
推荐回答(2个)
回答1:

∫cos2xdx=1/2∫cos2xd(2x) 令u=2x
=1/2∫cosudu
=1/2sinu+c
=1/2sin2x+c

回答2:

∫cos2xdx
=(1/2)∫cos2xd(2x)
=(1/2)sin2x+C