# Some homework questions

• Dec 3rd 2009, 06:10 PM
SOGGYMUFFIN
Some homework questions
1. Find the domain of the function f(x)=(4-x^2)

2. The revenue of a charter bus company depends the number of unsold seats, "s", per bus.

If the revenue, "R", in dollars, is given by R(s) = -2s^2+52s+5438, what is the maximum revenue?

3. Find an equation of the inverse of the function f(x) = (fifth root of 9-x)+4

• Dec 3rd 2009, 06:17 PM
pickslides
G'day Soggy Muffin

The answer to question 1 is the values of x that can be defined by the function. This is all real values.

For question 2 find the turning point of your parabola. Without using calculus this can be found by finding the midpoint of the 2 zeros

For question 3 rewrite the equation with a y instead of the f(x) then swap the x and y and solve for y.
• Dec 3rd 2009, 06:18 PM
Stroodle
Hi there.

For the first one, the domain is all the real values of x for which the function can be defined.

For the second one, as it's a quadratic function, if you convert it to turning point form, it should be clear what the maximum value is.

And, for the last question if you let f(x) be y, then swap x with y, then solve this for y, you will obtain the inverse of the function.

*Edit - Pickslides beat me to it :) Thought I'd accidentally double posted for a second there :)