Posted by stacey graham on Friday, March 26, 2010 at 12:24am.
find the exact value given that cosA=(1/3) in quad I, sin B=(1/2) in quad 4, and sin C=(1/4) in quad 2
sin(AB)?

trig  Reiny, Friday, March 26, 2010 at 9:04am
if cosA = 1/3 in I, then sinA = √8/3 using Pythagoras
if sinB= 1/2 in IV, the cosB = √3/2
sin (AB) = sinAcosB  cosAsinB
= (√8/3)(√3/2)  (1/3)(1/2)
= (√24 + 1)/6