1. fundimental identies

use the fundimental identies to find the value of the trigonomic function.
sin 0, if cos 0 = 2/3 and 0 is in quadrant IV

1. -3/2
2. (3 square root 7)/7
3. 5/4
4. -( square root 5)/3

2. Originally Posted by wenatchee
use the fundimental identies to find the value of the trigonomic function.
sin 0, if cos 0 = 2/3 and 0 is in quadrant IV

1. -3/2
2. (3 square root 7)/7
3. 5/4
4. -( square root 5)/3
Is your 0 supposed to represent $\theta$?

Make use of the Pythagorean Identity:

$\cos^2{\theta} + \sin^2{\theta} = 1$

$\left(\frac{2}{3}\right)^2 + \sin^2{\theta} = 1$

$\frac{4}{9} + \sin^2{\theta} = 1$

$\sin^2{\theta} = \frac{5}{9}$

$\sin{\theta} = \pm \frac{\sqrt{5}}{3}$.

Since $\theta$ is in Quadrant 4, we know $\sin{\theta}< 0$.

So $\sin{\theta} = -\frac{\sqrt{5}}{3}$.

3. Originally Posted by wenatchee
use the fundimental identies to find the value of the trigonomic function.
sin 0, if cos 0 = 2/3 and 0 is in quadrant IV

1. -3/2
2. (3 square root 7)/7
3. 5/4
4. -( square root 5)/3
I take it that by "0", you mean $\theta$.

So...

$\sin\theta=\sqrt{1-\cos^2\theta}$

Can you see what needs to be done?

4. Originally Posted by VonNemo19
I take it that by "0", you mean $\theta$.

So...

$\sin\theta=\sqrt{1-\cos^2\theta}$

Can you see what needs to be done?
Beat ya

5. Originally Posted by Prove It
Beat ya
You did indeed, you scoundrel! Until we meet again, Proveit!

6. slowly

Thanks I left my book and calculator at school and missed this whole section due to swine flu.

7. Originally Posted by wenatchee
Thanks I left my book and calculator at school and missed this whole section due to swine flu.
Where you from? In the US, I mean.

8. how do you get all the math symbols

9. malaga washington

10. You get the math symbols using LaTeX.

Go to the LaTeX help sub-forum on this site, and read through the tutorials.

11. Where in Austrailia are you from? I used to live in Sydney for about 6 months.

12. Melbourne, but I am currently living in Mildura.