Posted by **Nan** on Friday, December 29, 2006 at 4:24pm.

Given:

cos u = 3/5; 0 < u < pi/2

cos v = 5/13; 3pi/2 < v < 2pi

Find:

sin (v + u)

cos (v - u)

tan (v + u)

First compute or list the cosine and sine of both u and v.

Then use the combination rules

sin (v + u) = sin u cos v + cos v sin u.

cos (v - u) = cos u cos v + sin u sin v

and

tan (u + v) = [tan u + tan v]/[1 - tan u tan v]

We got sin u = 4/5 & sin v = SQRT (7/13)

## Answer this Question

## Related Questions

- math - Use the exact values of the sin, cos and tan of pi/3 and pi/6, and the ...
- math - Use the exact values of the sin, cos and tan of pi/3 and pi/6, and the ...
- Mathematics - Trigonometric Identities - Let y represent theta Prove: 1 + 1/tan^...
- TRIG! - Posted by hayden on Monday, February 23, 2009 at 4:05pm. sin^6 x + cos^6...
- precalculus - For each of the following determine whether or not it is an ...
- trig - Reduce the following to the sine or cosine of one angle: (i) sin145*cos75...
- Trigonometry - Please review and tell me if i did something wrong. Find the ...
- Pre-calculus help - I have two problems I am stuck on, if you could show me how ...
- calculus - Differentiate. y= (cos x)^x u= cos x du= -sin x dx ln y = ln(cos x)^x...
- Calc. - Differentiate. y= (cos x)^x u= cos x du= -sin x dx ln y = ln(cos x)^x ln...