## ihatealgebrasomuch Group Title is the trigonometric ratio of cos225degrees 1? (im in the unit circle) one year ago one year ago

1. dpaInc Group Title

no.... cos (225 degrees) is NOT 1

2. dpaInc Group Title

since you're on the unit circle.... look at the x-coordinate of 225 degrees...

3. dpaInc Group Title

cos (225 degrees) = the x-coordinate of the point on the unit circle.

4. ihatealgebrasomuch Group Title

im confused though, because if its a right triangle, and the reference angle is 45 degrees, then the opposite angle is also 45 degrees, making it a 45-45-90 triangle and the two legs' side lengths are the same so they would both be |dw:1359842106830:dw|

5. dpaInc Group Title

$$\large cos(225 ^\circ)=-\frac{\sqrt2}{2}$$ $$\large tan (225 ^\circ)=\frac{\frac{\sqrt2}{2}}{-\frac{\sqrt2}{2}}=-1$$

6. ihatealgebrasomuch Group Title

|dw:1359842455017:dw|

7. ihatealgebrasomuch Group Title

its just negative square root 2 /2?