# Easy precal question

1. Oct 18, 2005

### raross

Can someone help me with a few simple problems:

These 0's have lines through them, and are slanted. I used 0\ to represent that.

1.) If sin0\ = 3/5 and 0\ is in quadrant II, find sin 2(0\). (Hint: sin 2(0\) = 2 sin 0\ cos 0\)?

2.) The trigonometric expression, sin 0$$cot 0\ + tan 0$$, is equilvalent to which of the following?
(A) sec(0\)
(B) sin(0\)
(C) 1
(D) sin^2(0\)
(E) csc(0\)

3.) The trigonometric expression, sin 0\ + cot 0\ cos 0\, is equivalent to which of the following?
(A) sec 0\
(B) csc 0\
(C) 2 sin 0\
(D) 1
(E) cos^2(0\)

2. Oct 18, 2005

### *melinda*

I'm guessing that any "0's with slanted lines through them" would be the greek letter theta, which looks like this: $\theta$.

Beyond that, I really cannot help you unless you show some work and show where you got stuck.

I'm sure that your pre calc book contains all the necesary trig identites, and hopefully some example problems as well.

3. Oct 18, 2005

### EnumaElish

For 1, first derive what theta is, then calculate cos. For 2-3, use trig identities in your textbook or see the links here.

4. Oct 18, 2005

### sanitykey

If you are still stuck, for questions 2 and 3 the relevant trig identities are

tan$\theta$=sin$\theta$/cos$\theta$

cot$\theta$=1/tan$\theta$