∫(sinx)^6dx
=(1/8)∫(1-cos2x)^3dx
=(1/8)∫[1-(cos2x)^3+3(cos2x)^2-3cos2x]dx
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其中
∫(cos2x)^3dx=(1/2)∫1-(sin2x)^2dsin2x=(1/2)[sin2x-(1/3)(sin2x)^3]
∫(cos2x)^2dx=(1/2)∫[cos4x+1]dx=(1/2)[(1/4)sin4x+x]
∫cos2xdx=(1/2)sin2x
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=(1/8){x-(1/2)[sin2x-(1/3)(sin2x)^3]+(3/2)[(1/4)sin4x+x]-(3/2)sin2x}
=5x/2+(sin2x)^3/6+3sin4x/8-5sin2x/2