26. The point C (-3,1) is rotated 90° clockwise about the origin. What are the coordinates of C’?

D. (1,-3)
E. (1,3)
F. (3, -1)

1 answer

To rotate a point 90° clockwise about the origin, we can use the following rotation formula:

(x', y') = (x*cosθ - y*sinθ, x*sinθ + y*cosθ)

In this case, since we want to rotate 90° clockwise, we can substitute θ with -90° or -π/2 radians.

Using the formula, we can calculate the new coordinates:

(x', y') = (-3*cos(-π/2) - 1*sin(-π/2), -3*sin(-π/2) + 1*cos(-π/2))

But cos(-π/2) = 0 and sin(-π/2) = -1, so we have:

(x', y') = (-3*0 - 1*(-1), -3*(-1) + 1*0)
(x', y') = (0 + 1, 3 + 0)
(x', y') = (1, 3)

Therefore, the coordinates of C' are (1, 3). Therefore, the correct answer is E. (1, 3).