Posted by Sammy on Monday, June 25, 2012 at 8:09pm.
If Sin A=3/5 and cos B= 12/13, find the value of sin(AB) if Angle A is in Quadrant I and angle B is in Quadrant III.

Precalculus  Steve, Tuesday, June 26, 2012 at 12:08am
in QI, sinA=3/5 means cosA = 4/5
in QIII, cosB = 12/13 means sinB = 5/13
sin(AB) = sinAcosB  cosAsinB = (3/5)(12/13)  (4/5)(5/13) = (36+20)/65 = 16/65