Posted by **House** on Friday, October 3, 2008 at 1:02pm.

If 0<theta<90 and tan theta= (square root 3)/2, find cos theta?

tan(t) =ã3 /2; cos(t) = 1/ã(1+(tant)^2)= 1/ã(1+3/4) = 2/ã7

right or wrong?

- Math -
**Reiny**, Friday, October 3, 2008 at 4:45pm
You are doing this the hard way.

make a diagram

since tan theta = √3/2, and tan theta = opposite/adjacent, make the oppose √3 and the adjacent 2

In your head you could do Pythagoras and get the hypotenuse √7

since cos theta = adjacent/hypotenuse

cos theta = 2/√7

which is what you got.

## Answer This Question

## Related Questions

- math - I have a question I have been working on since yesterday and I am not ...
- Maths- complex numbers - Find tan(3 theta) in terms of tan theta Use the formula...
- Calculus - I wanted to confirm that I solved these problems correctly (we had to...
- Algebra II - Multiple Choice (theta) means the symbol 0 with the dash in it. 1.)...
- Trigonometry - Prove the following identities: 1. (tan theta - sin theta)^2 + (1...
- Trigonometry - Prove the following identities: 1. (tan theta - sin theta)^2 + (1...
- Trigonometry - Thank you STEVE!!!!! Suppose that Cos (theta) = 1/square root 2 ...
- Trig - 1. Establish the identity: sin(theta+3pi/2)=-cos(theta) 2. Find the exact...
- math - Another: theta is a second quadrant angle in standard position and tan ...
- math - There are no typos and no work b/c I don't know how to do them. Thanks. 1...

More Related Questions