## anonymous one year ago What is sin Pi/4 in a unit circle?

1. anonymous

2. jim_thompson5910

use this unit circle http://www.regentsprep.org/Regents/math/algtrig/ATT5/600px-Unit_circle_angles_svg.jpg locate the angle pi/4 then find the corresponding point on the unit circle for angle pi/4 what is the y coordinate of that point?

3. anonymous

is it 45 degrees?

4. jim_thompson5910

45 degrees = pi/4 radians the final answer isn't 45 degrees though

5. anonymous

i'm not sure what to do after then....

6. jim_thompson5910

look at the attached image notice how I'm circling the point when the angle is pi/4

7. jim_thompson5910

what point did I circle? what is the y coordinate of that point?

8. anonymous

sqrt 2/2?

9. jim_thompson5910

therefore, $\Large \sin\left(\frac{\pi}{4}\right) = \frac{\sqrt{2}}{2}$

10. jim_thompson5910

the y coordinate corresponds to sine the x coordinate corresponds to cosine

11. anonymous

so the answer is Pi/4?

12. anonymous

the answer is 1/root2

13. anonymous

sorry, i meant sqrt 2

14. jim_thompson5910

Another example, $\Large \sin\left(\frac{\pi}{3}\right) = \frac{\sqrt{3}}{2}$

15. anonymous

i understood, i just typed the wrong thing that iwas trying to say. but thank you!

16. jim_thompson5910

no problem