# Precalculus

posted by .

If Sin A=3/5 and cos B= -12/13, find the value of sin(A-B) if Angle A is in Quadrant I and angle B is in Quadrant III.

• Precalculus -

in QI, sinA=3/5 means cosA = 4/5
in QIII, cosB = -12/13 means sinB = -5/13

sin(A-B) = sinAcosB - cosAsinB = (3/5)(-12/13) - (4/5)(-5/13) = (-36+20)/65 = -16/65

## Similar Questions

1. ### trig

Suppose sin theda= – 3/5 and theda is a Quadrant III angle. Find the exact value of sin 2 theda and cos 2 theda.
2. ### Trig

Find cos(s+t) if cos s= -1/2 and sin t= 3/5, s and t are in quadrant II. I got the answer to be -4/10 plus -3sqrt(3)/10. Is that right?
3. ### Math!!!

angle x is in the second quadrant and angel y is in the first quadrant and angle y is in the first quardrant such that sin x=5/13 and cos y = 3/5. Determine and exact value for cos x.
4. ### Math Trig Find Quadrant I II III IV

In which quadrant is the terminal side of angle A?
5. ### precalculus

find the values of the requested trig functions using the given value and quadrant in which the point corresponding to the angle lies. quadrant II; sinθ=4/5 find cosθ and tan θ
6. ### Trigonometry

Suppose *u* is a quadrant IV angle with cos(u) = 3/5. Suppose *v* is a quadrant IV angle with cos(v) = 12/13. Find the exact value of sin(u-v) I have gotten to sin120cos150 - sin150cos120 but I am not sure I am correct up to that point …
7. ### Pre-Cal

Find sin 2x, cos 2x, and tan 2x from the given information. [1]. sin x = 8/17, x in Quadrant I 1). sin 2x =________. 2). cos 2x =________. 3). tan 2x =________. [2]. sin x = -5/13, x in Quadrant III 1). sin 2x =________. 2). cos 2x …
8. ### Trig

1. Given Sin(A) = ⅗ and Cos(B) = 8/17 in Quadrant I, find Sin(A+B). a) 24/80 [b)] 84/85 c) 60/80 d) 60/85 Find Cos(A+B). a) 32/80 b) -45/85 c) -13/80 [d)] -13/85 Find Tan(A+B) a) 0.8 [b)] -1.72 c) -4.21 d) -6.46 I keep getting …
9. ### Pre calc

sin(θ − ϕ); tan(θ) = 5/12 θ in Quadrant III, sin(ϕ) = − sqaure root10/10 ϕ in Quadrant IV. I used the sin equation sin(a)cos(b)-sin(a)cos(b) However I am still getting the wrong answer