计算定积分:∫cosx(1+sinx)dx,(区间0到π/2 )

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计算定积分:∫cosx(1+sinx)dx,(区间0到π/2 )
计算定积分:∫cosx(1+sinx)dx,(区间0到π/2 )

计算定积分:∫cosx(1+sinx)dx,(区间0到π/2 )
=∫cosxdx+∫sinxcosxdx
=sinx+(1/2)∫sin2xdx
=sin(π/2)-sin0+(1/4)∫sin2xd2x
=1-(1/4)cos2x
=1-(1/4)(cosπ-cos0)
=1+1/2
=1.5

原式=(cosx+1/2sin2x)dx=sinx-1/4cos2x
再代入就行了,结果是3/2

∫cosx(1+sinx)dx,(区间0到π/2 )
=∫(1+sinx)dsinx,(区间0到π/2 )
=(1/2)(1+sinx)^2,(区间0到π/2 )
=(1/2)*2^2-(1/2)
=3/2

∫cosx(1+sinx)dx
=∫(1+sinx)dsinx
=sinx+1/2(sinx)^2
=sin(π/2)-sin(0)+1/2[sin(π/2)]^2-1/2[sinx(0)]^2
=3/2