化简sin18*cos36
问题描述：
化简sin18*cos36
答
sin18*cos36=sin18*cos36*sin72/sin72=sin18*cos36*sin72/sin72=sin18*cos36*cos18/sin72=(sin18*cos18)*cos36/sin72=(1/2sin36)*cos36/sin72=1/4sin72/sin72=1/4