The image of the point [tex][tex]$(1,-2)$[/tex][/tex] after a rotation of [tex][tex]$-180^{\circ}$[/tex][/tex] about the origin is:

A. (2, -1)
B. (1, 2)
C. [tex][tex]$(-2,1)$[/tex][/tex]
D. [tex][tex]$(-1,2)$[/tex][/tex]



Answer :

To solve this problem, we need to determine the new coordinates of the point [tex]\((1, -2)\)[/tex] after a rotation of [tex]\(-180^\circ\)[/tex] about the origin. A rotation of [tex]\(-180^\circ\)[/tex] about the origin essentially flips the point to the exact opposite position across the origin.

Here is a step-by-step explanation:

1. Understand the Rotation by [tex]\(-180^\circ\)[/tex]:

Rotating a point by [tex]\(-180^\circ\)[/tex] is equivalent to rotating the point [tex]\(180^\circ\)[/tex] in the clockwise direction, which is the same as rotating it [tex]\(180^\circ\)[/tex] in the counterclockwise direction. The effect of a [tex]\(180^\circ\)[/tex] rotation is that both the x and y coordinates of the point will change signs.

2. Applying the Rotation:

The coordinates after a [tex]\(180^\circ\)[/tex] rotation from [tex]\((x, y)\)[/tex] become [tex]\((-x, -y)\)[/tex].

3. Calculate the New Coordinates:

For the point [tex]\((1, -2)\)[/tex], after a [tex]\(-180^\circ\)[/tex] rotation, the new coordinates will be:
[tex]\[ (-1 \cdot 1, -1 \cdot -2) = (-1, 2). \][/tex]

Hence, after a rotation of [tex]\(-180^\circ\)[/tex] about the origin, the point [tex]\((1, -2)\)[/tex] moves to [tex]\((-1, 2)\)[/tex].

So, the correct answer is [tex]\(\boxed{(-1,2)}\)[/tex].