How do you prove the reduction identities #Sin(x+pi)= -sin(x)# using a unit circle diagram?
1 Answer
Jun 27, 2015
Explanation:
On the trig unit circle,
If x is in Quadrant I, (x + pi) is in Quadrant III -> sin (x + pi) = - sin x
If x is in Quadrant II, (x + pi) is in Quadrant IV -> sin (x = pi) = - sin x
