# Which of these functions have inverse(s) and why?

• January 27th 2010, 05:48 PM
Marino
Which of these functions have inverse(s) and why?
a) f(x) = 10^x

b) f(x) = x^2 - 10

c)
_x_|_f(x)_
..-3|-1
..-1|0
...0|-1
...2|3
• January 27th 2010, 06:14 PM
battleman13
I'll get you started...

f(x) for any x should give a unique answer... if it does not then your function has no inverse

examine f(x) = $x^2$
• January 27th 2010, 06:21 PM
VonNemo19
Quote:

Originally Posted by Marino
a) f(x) = 10^x

b) f(x) = x^2 - 10

c)
_x_|_f(x)_
..-3|-1
..-1|0
...0|-1
...2|3

Do you know

1. The definition of an inverse function

2. The horizontal line test?
• January 27th 2010, 06:25 PM
Marino
Yes, I know what an inverse function is. It's when the dependent and independent variables of a function are interchanged.
No, I've never heard of the horizontal line test before.
• January 27th 2010, 07:35 PM
Stroodle