How can we see the geometric equivalence between cos(theta + pi/2) and -sin(theta) (and by extension sin(theta + pi/2) and cos(theta))?

minhsual

How can we represent rotation in the clock-wise direction? Is there an advantage in rotating clock-wise or counter-clock wise to arrive at the same position?

How can we see the geometric equivalence between cos(theta + pi/2) and -sin(theta) (and by extension sin(theta + pi/2) and cos(theta))?

How can we represent rotation in the clock-wise direction? Is there an advantage in rotating clock-wise or counter-clock wise to arrive at the same position?