## ihatealgebrasomuch 2 years ago is the trigonometric ratio of cos225degrees 1? (im in the unit circle)

1. dpaInc

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

2. dpaInc

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

3. dpaInc

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

4. ihatealgebrasomuch

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

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

6. ihatealgebrasomuch

|dw:1359842455017:dw|

7. ihatealgebrasomuch

its just negative square root 2 /2?