=∫[(1+cos6x)/2]³dx=1/8∫(1+3cos6x+3cos²6x+cos³6x)dx=1/8[∫dx+3∫cos6xdx+∫3cos²6xdx+∫cos³6xdx]=1/8[x+1/2∫cos6xd6x+1/4∫(1+cos12x)/2d12x+1/6∫(1-sin²6x)dsin6x]=1/8[x+1/...