105k views
1 vote
Describe in your own words how you find the coordinates for any point (x, y) when it is rotated 90 degrees counterclockwise about the origin.

Show a graph and an example of this type of rotation.

User EliuX
by
6.2k points

1 Answer

6 votes

Answer:

Considering the point
(x, y)

If you represent it as a complext number, you get:

- Counterclockwise if multiplying by
i\\

- Clockwise if multiplying by
-i

Note, I'm considering
x+iy

Another approach using trigonometry is considering:


(x,y)=(cos\theta,sin\theta)

So the rotation will get the coordinates


(cos\theta+(\pi)/(2) ,sin\theta+(\pi)/(2))

User Stephan Unrau
by
5.6k points