Question

A point P is reflected first in the y-axis and then in the origin to get the point (6, 6). The co-ordinates of the point P are ______.

Options

• (6, −6)

• (−6, −6)

• (−6, 6)

• (6, 6)

Answer 1

A point P is reflected first in the y-axis and then in the origin to get the point (6, 6). The co-ordinates of the point P are (6, −6).

Explanation:

Let co-ordinates of point P are (x, y) and P" be (6, 6).

We know that,

On reflecting in y-axis the sign of x co-ordinate changes.

Let on reflection in y-axis P(x, y) becomes P'.

⇒ P' = (−x, y)

We know that,

On reflecting in origin the sign of both x and y co-ordinate changes.

Let on reflection in origin P'(−x, y) becomes P".

⇒ P" = (x, −y)

⇒ (6, 6) = (x, −y)

⇒ x = 6 and −y = 6

⇒ x = 6 and y = −6.

P = (x, y) = (6, −6).