# Trigonometry

If sinA + sinB = a and cosA + cosB = b, find the value of tanA-B/2

1. 👍 2
2. 👎 1
3. 👁 1,732

sinA + sinB = 2 sin(A+B)/2 cos(A-B)/2
cosA + cosB = 2 cos(A+B)/2 cos(A-B)/2

That should get you started.

1. 👍 2
2. 👎 9
2. a/b is a value of tan[A-B/2]

1. 👍 1
2. 👎 6

1. 👍 9
2. 👎 2

## Similar Questions

1. ### Math

if sinA+sinB=x and cosA-cosB=y then find tan[(A-B)/2]

2. ### Pre-Calculus

If sinA=3/5 when pi/2 < A < pi and cosB=5/13 when 3pi/2 < B < 2pi, find the exact value of the function cos(5pi/6+B).

3. ### Trigonometry

Prove that 1-cosA+cosB-cos(A+B)/1+cosA-cosB-cos(A+B) = tanA/2cotA/2

4. ### math

if cos(B-C)+cos(C-A)+cos(A-B)=-3/2 then prove that cosA+cosB+cosC=O and sinA+sinB+sinC=O after that prove that cos(B-C)=cos(C-A)=cos(A-B)=-1/2

1. ### Math

prove that sinA/(1+cosA) + (1+cosA)/(sinA) = 2cosecA

2. ### Math

If A and B are acute angle such that SinA=8/17 and CosB=3/5.Find 1, Cos(A+B) 2, Sin(A+B) 3, Sin(A-B)

3. ### trig

If A+B+C=^(^=180) prove that sinA + sinB - sinC = 4sinA/2 sinB/2 cosC/2

4. ### Maths

Given that sinA=2/5 and that A is obtuse,find the value of cosA. 👍 0 👎 0 👁 25 asked by Raj yesterday at 4:18am sinA = 2/5, so cosA = √21/5 But A is in QII, so cosA = -√21/5 👍 0 👎 0 posted by oobleck yesterday at

1. ### maths

If cosA + sinA= root2 cosA Show that cosA - sinA= root2 sinA

2. ### Pre-calculus (Trigonometry)

The rotating spotlight from the Coast Guard ship can illuminate up to a distance of 250 m. An observer on the shore is 500 m from the ship. HIs line of sight to the ship makes an angle of 20 degrees with the shoreline. What length

3. ### trig

if 8 tan Q=15 then sinA-cosA=?

4. ### trigonometry

Prove : 1 + Sin2A/ Cos2A = CosA + SinA / CosA- SinA