Find the sine of 225°.

sin225=sin(180+45) 
sin(180+45)=-sin45 
from special angles we know that sin45=1/root2 
hence sin225=-1/root2 

cos225=cos(180+45) 
cos(180+45)=-cos45 
from special angles we know that cos 45=1/root2 
hence cos225=-1/root2 

tan225=tan(180+45) 
tan(180+45)=tan 45 
from special angle we know that tan45=1 
hence tan225=1 

Find the sine of 150°.

sin 150 = sin (180 - 30) = sin (2 x 90' - 30) = sin 30 = 1/2 <==ANSWER 

Find the sine of 300°.

sin(300) = sin(360-60) = -sin60 = -root(3)/2

Find the sine of 315 

Using unit circle, 

sin(315) = sin(7π/4) 
sin(315) = -√2 / 2 
sin(315) ≈ -0.71 
Your graph of sin(315) should be the following point on a X_Y coordinate. 
(x, y) = (5.50, -0.71) 

cos(315) = cos(7π/4) 
cos(315) = √2 / 2 
cos(315) ≈ 0.71 
Your graph of cos(315) should be the following point on a X_Y coordinate. 
(x, y) = (5.50, 0.71) 

tan(x) = sin(x) / cos(x) 
tan(315) = tan(7π/4) 
tan(315) = sin(315) / cos(315) 
tan(315) = (-√2 / 2) / (√2 / 2) 
tan(315) = -1 
Your graph of tan(315) should be the following point on a X_Y coordinate. 
(x, y) = (5.50, -1) 

.Find the sine of 0 degrees

• cos 0° = 1, sin 0° = 0 and tan 0° = 0