Posted by **aaa** on Saturday, February 2, 2013 at 4:40am.

kos^2 theta - sin^2 theta = 0.25

- Math(Trigonometry) -
**Reiny**, Saturday, February 2, 2013 at 8:40am
the left side is a well know identity,

cos^2 A - sin^2 A = cos 2A

so we have:

cos 2Ø = 1/4

2Ø = 75.52° or 2Ø = 284.48°

Ø = 37.76° , 142.24°, ...

or

Ø = .659 , 2.4825 ... in radians

general solution in radians:

.659 + kπ/2 , where k is an integer,

2.4825 + kπ/2, where k is an integer.

general solution in degrees:

37.76° + 90k° , 142.24° + 90k°

## Answer this Question

## Related Questions

- trigonometry - can you correct the rest for me please? Express each as a ...
- trigonometry - can you correct the rest for me please? Express each as a ...
- Calculus - I wanted to confirm that I solved these problems correctly (we had to...
- math(Trigonometry) - sin 2 theta + cos theta = 0 so, we use sin 2 theta = 2 sin ...
- Trigonometry - Thank you STEVE!!!!! Suppose that Cos (theta) = 1/square root 2 ...
- Mathamatics - Solve the following trigonometry identities. a) 1-cos2(theta) = ...
- Algebra II - Multiple Choice Which expression is NOT equivalent to 1? (theta) ...
- Trigonometry - Simplify each expression using fundamental identities. 1. Sin ...
- Math - Trigonometry - If sin theta +cos theta =1.2, then what is sin^3 theta + ...
- Trigonometry - express in terms of sine and cosine. a) tan theta/ cot theta i ...