Posted by **Shasha** on Tuesday, November 27, 2012 at 11:04pm.

What is the exact value of sin(2 theta) if cos (theta)=3/5 and (theta) is in quadrent 4?

12/25

24/25

-12/25

-7/25

-24/25

- calculus -
**Jennifer**, Wednesday, November 28, 2012 at 3:13pm
cos(theta) = 3/5

Use your calculator:

cos-1(3/5) = theta = 53.13 degrees

This is the value that your calculator gives, and it is in quadrant; To find the value theta corresponding to quadrant 4, notice the symmetry in a graph of cos x, which is that cos(x), cos(x) = cos(360 - x); 306.87 = theta in quadrant 4

quadrant 1 (0 - 90 degrees)

quadrant 2 (90 - 180 degrees)

quadrant 3 (180 - 270 degrees)

quadrant 4 (270 - 360 degrees)

Use your calculator to calculator sin(2*306.87)

## Answer this Question

## Related Questions

- Calculus - I wanted to confirm that I solved these problems correctly (we had to...
- Shasha - What is the exact value of sin(2 theta) if cos (theta)=3/5 and (theta) ...
- Trig - 1. Establish the identity: sin(theta+3pi/2)=-cos(theta) 2. Find the exact...
- Algebra II - Multiple Choice Which expression is NOT equivalent to 1? (theta) ...
- Algebra II - Multiple Choice (theta) means the symbol 0 with the dash in it. 1.)...
- Math - angle theta is in the standard position and 0'=<theta=<180'. If cos...
- Precalculus check answers help! - 1.) Find an expression equivalent to sec theta...
- Precalculus check answers help! - 1.) Find an expression equivalent to sec theta...
- Trig - Find the exact value of sin2(theta) if cos(theta) = -sqrt 5/3 and 180 <...
- trig - If sin theta is equal to 5/13 and theta is an angle in quadrant II find ...

More Related Questions