利用公式cos2x=1-2(sinx)^2(sinx)^2=(1-cos2x)/2cos4x=2(cos2x)^2-1(cos2x)^2=(cos4x+1)/2∫(sinx)^6 dx=∫[(sinx)^2]^3 dx=∫[(1/2-cos2x/2)]^3 dx=1/8∫(1-cos2x)^3 dx=1/8∫[1-3cos2x+3(cos2x)^2-(cos2x)^3] dx=1...