Homework Help: trig

Posted by Kenneth on Sunday, January 8, 2012 at 6:45pm.

how do you work find sin (a-B)beta sign. sin a = 12/13,a lies in quadrant II,and cos B = 15/17, B lies in quadrant I.

trig - Steve, Monday, January 9, 2012 at 4:56am
Can't quite figure out some of the verbage, but

if A is in QII and sinA = 12/13, the cosA = -5/13

if B is in QI and cosB = 15/17, then sinB = 8/17

So,

sin(A-B) = sinAcosB - cosAsinB
= (12/13)(15/17) - (-5/13)(8/17)
= 180/221 + 40/221 = 220/221

Related Questions

trig - Find cos(a=b). sin a = 3/5, a lies in Quadrant II, and cos b = 5/13, b ...
mth, trig - Given cos a=-7/25 in quadrant II , and sin b=-12/13, in quadrant IV...
trig - If sin alpha = -3/5, sin beta = -5/13, P(alpha) is in the third quadrant...
Trig - Find cos(s+t) if cos s= -1/2 and sin t= 3/5, s and t are in quadrant II. ...
Pre-calc/Trig - If cot(a)=3 and sin(b)= (15/17) where a being alpha lies in ...
Alg2/Trig - Find the exact value of the trigonometric function given that sin u...
math - sin a=3/5, a lies on quadrant 1 and sin b=5/13, b lies on quadrant 2. ...
trig - Given sin a = 15/17 with a in Quadrant I and cos beta = 4/5 with beta in ...
Pre-Calculus - If sin(theta)=15/17 and cos(beta)=(-5/13 (both theta and beta are...
trig - Given that sin = 3/5 and lies in quadrant II, find the following value. ...

For Further Reading

First Name:
School Subject:
Answer: