Diketahui sin A = 8/17 dan tan B = 12/5, A sudut tumpul dan B sudut lancip. Nilai (A+B) =

coba nilai sin (A+B)= ...

sin A = 8/17 = y/r
triple pitagoras  x,y,r = 15, 8, 17
cos A = x/r =  -15/17

tan B = 12/5= y/x
triple pitagoras x,y, r = 5, 12, 13
sin B = y/r= 12/13
cos B = x/r = 5/13

sin (A+B)= sin A cos B + cos A sin B
sin (A+B) = (8/17 x 5/13) + (-15/17 x 12/13)
sin (A+B) = 40/221 - 180/221 = - 140/221