# The function of the bottom half of the circle x 2 + y 2 = 9

### Precalculus: Mathematics for Calcu...

6th Edition
Stewart + 5 others
Publisher: Cengage Learning
ISBN: 9780840068071

### Precalculus: Mathematics for Calcu...

6th Edition
Stewart + 5 others
Publisher: Cengage Learning
ISBN: 9780840068071

#### Solutions

Chapter 2.2, Problem 78E
To determine

## To find : The function of the bottom half of the circle x2+y2=9

Expert Solution

The equation for the bottom half of the circle is f(x)=9x2 for [3,3]

### Explanation of Solution

Given information :

The equation of the circle is x2+y2=9

Calculation :

Solve the equation for y :

x2+y2=9                      [original equation]x2+y2x2=9x2       [subtract x2 from both sides]y2=9x2y2=9x2                [take square roots on both sides]|y|=9x2y=±9x2y=9x2                     [keep the negative half for the bottom of the circle]f(x)=9x2            [set y=f(x)]f(x)=9x2 for [3,3]

Hence,

the equation for the bottom half of the circle is f(x)=9x2 for [3,3]

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