sin∧2a+sin∧2b+2sina*sinb*cos(a+b).化简,

sin∧2a+sin∧2b+2sina*sinb*cos(a+b).化简,
sin∧2a+sin∧2b+2sina*sinb*cos(a+b).化简,

sin∧2a+sin∧2b+2sina*sinb*cos(a+b).化简,
sin^2a+sin^2b+2sina*sinb*cos(a+b)
=sin^2a+sin^2b+2sina*(cosacosb-sinasinb)
=(1-cos2a)/2+(1-cos2b)/2+sinasinb/2-(1-cos2a)(1-cos2b)/2
=(1+sinasinb-cosacosb)/2
=[1+sin(a-b)]/2