Question

Find the exact value of cos135degrees. Tell the quadrant

Answer 1

Have you ever used a unit circle before?

Answer 2

Yes

Answer 3

Ok, awesome. Pull one up. What is the coordinate at 135 degrees?

Answer 4

3pi/4

Answer 5

That's the converted pi value. We need the actual coordinates

Answer 6

Do you know where the coordinates are?

Answer 7

I dont have that on my chart yet

Answer 8

Okay. That's probably why you're having issues with this.
Take a look at this and fill in your chart
http://etc.usf.edu/clipart/43200/43215/unit-circle7_43215_lg.gif

Answer 9

So essentially, the coordinates are (cos, sin). So if at pi/3 degrees, the coordinates are (1/2, sqrt3/2), then cos=1/2 and sin=sqrt3/2. Does that make sense?

Answer 10

I think I get it

Answer 11

So at the coordinate of 135, what is the value of cos?

Answer 12

sqroot2/2?

Answer 13

Careful, remember the coordinates are (cos, sin)