Question

Find the co-ordinate of the image of the point A (3, -2) when it is reflected on the line x=0 and then rotated about origin through -90​

Answer 1

Explanation:

Rotations are easy when its multiples of 90 degrees; 90,180,270,360. Treat them like they’re a complex number like [x+yi]*i=[-y,xi] so rotating by 90 degrees and 180 is i squared [-1]! So [-3,2] rot90 is [-2,-3].

Reflection about the y=x line is change places. [x.y]=[y,x].

So [-2.-3] reflected about the y=x line is [-2.-3]=[-3.-2],

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