mohon bantuannya nomor 7

sin(a-b)= sin a cos b- cos a sin b
akar3 /2 = 1/2-cos a sin b
akar3 /2-1/2=-cos a sin b
cos a sin b = -1+akar3 /2
a. sin(a+b)=sin a cos b+ cos a sin b
= 1/2 + (-1+akar3 /2 )
= akar3 /2
b. sin (a+b)/sin (a-b)= (akar3/2)/(-1+akar3 /2)
= 3+akar3 /2

maaf jika salah