97.0k views
3 votes
A circle is translated 4 units to the right and then reflected over the x axis. What statement will always be true of the circle at the new location?

1 Answer

1 vote

Answer:

The statements are not given, so i will answer it in the most general way possible:

First, let's recall two things:

Horizontal translation.

For a number A positive, we can move the graph of f(x) by A units to the right by the transformation g(x) = f(x - A)

Reflection over x

For a point (x, y), a reflection over the x-axis transforms this point into (x, - y).

Now let's analyze the problem:

A generic circle, of radius R and centered in the point (a, b) can be written as:

(x - a)^2 + (y - b)^2 = R^2.

Now let's translate this 4 units to the right:

(x - 4 - a)^2 + (y - b)^2 = R^2.

or in standard circle notation:

(x - (4 + a))^2 + (y - b)^2 = R^2.

Now the circle is centered in the point (a + 4, b).

Now let's do a reflection over the x-axis.

This means that the sign of y changes, so now we have:

(x - (4 + a))^2 + (-y - b)^2 = R^2.

But because the term with y is squared, this is the same than:

(x - (4 + a))^2 + (y + b)^2 = R^2.

Or, in standard circle notation:

(x - (4 + a))^2 + (y - (-b))^2 = R^2.

Then the circle is now centered in point (a + 4, -b).

So now you know where the circle is located, and also you can see that the radius of the circle never changed.

User Abdur
by
8.0k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories