Question

Find mirror image of point representing x+i y on imaginary axis.

(a) (x, y)

(b) (-x, -y)

(c) (-x, y)

(d) (x, -y)

This question was posed to me in an international level competition.

I need to ask this question from Argand Plane and Polar Representation topic in section Complex Numbers and Quadratic Equations of Mathematics – Class 11

Answer 1

Right choice is (c) (-x, y)

Explanation: Mirror image of point (x, y) on imaginary axis is (-x, y).

Since imaginary axis is acting as mirror y-coordinate remains same whereas x-coordinate gets inverted. So, (-x, y) is mirror image of (x, y) on imaginary axis.