# Exact value of tan

1. Oct 11, 2004

### Maria

How do I find the exact value of tan 165 and tan 285
I think it has got something to do with
sinx
tanx = cosx

2. Oct 11, 2004

### Motifs

Susan meets Maria on PF ground and ready to fight

The best best way is use a calculator!
The best way is pi/12=pi/3-pi/4 and then try applying the formula calculating tan(pi/3-pi/4), your goning to get there

Susan

Last edited: Oct 11, 2004
3. Oct 11, 2004

### Maria

thats not enough on a test

4. Oct 11, 2004

### Hurkyl

Staff Emeritus
do you know how to find sin 165?

5. Oct 11, 2004

### Motifs

why not enough ?

6. Oct 11, 2004

### Maria

Ive found sin 165 and tan 165,and Ive tried
sinx
tanx = cosx
but I cant get the answer right..

7. Oct 11, 2004

### Hurkyl

Staff Emeritus
All right, I'm confused as to just what you're trying to do... I thought you said you were unable to find tan 165?

8. Oct 11, 2004

### Maria

oh sorry..
sin165
What I meant was tan1 65 = cos165

I know sin 165and cos 165.. Have I got things right so far?

9. Oct 11, 2004

### Hurkyl

Staff Emeritus
Have you been trying to write tan 165 = sin 165 / cos 165?

If you have the right values for sin 165 and cos 165, then dividing will give you the right value for tan 165.

Keep in mind that there are lots of ways to write the exact value for tan 165, so if the answer doesn't look like the books answer, see if you can find a way to be sure they are the same or different.