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Rotation of the first volume of ninth grade mathematics
Polar coordinates are not introduced

For point A(x, y)

The distance to the origin is a= radical sign (x 2+y 2)

Let the angle between the vector OA and the positive direction of the x axis be t.

Then the coordinates of a can be written as (acost, asint).

Rotate m counterclockwise, the coordinates will become (acos(t+m), asin(t+m)), when m

For the case in question, a = (4 √ 2,0) = (4 √ 2cos0,4 √ 2sin0).

Turn clockwise 45, and b = (4 √ 2cos (-45), 4 √ 2sin (-45)) = (4, -4).