Question

Use the unit circle to find cos(-90o).

Answer 1

can you show the angle -90 degrees ?

Answer 2

What do you mean? Is it undefined?

Answer 3

@phi

Answer 4

no, it's defined. but the first step to this problem is drawing an x-axis and y-axis, and put in -90 degrees

Answer 5

you measure an angle from the x-axis (positive direction)
negative angles means move clockwise (i.e. down)
move 90 degees

Answer 6

On the unit circle?

Answer 7

Wait so is it (-1,0) @phi

Answer 8

Wait no (1,0)