Help =)
1 answer:
You might be interested in
Note that 
and 
.
From the unit circle, we can check that
and 
have the same value, but opposite signs, that is:
.
Thus,
.
Note that
is the x-coordinate of the lowest point on the unit circle, that is (0, -1). Thus 
Answer: 0
From the unit circle, we can check that
Thus,
Note that
Answer: 0