diketahui sin a =3/5,cos b=12/13,sudut a tumpul,sudut b lancip .sin(a+b) =…

sin a = 3/5 berarti cos a = -4/5
cos b = 12/13 berarti sin b = 5/13
sin (a+b) = sin a cos b + cos a sin b
= 3/5 . 12/13 + -4/5 . 5/13
= 36/65 - 20/65
= 16/65