327,943 views
45 votes
45 votes
Determining if two functions are inverses. 15 pts

Determining if two functions are inverses. 15 pts-example-1
User Haywood
by
3.2k points

2 Answers

16 votes
16 votes
The answer is the first one because u could see how it is but I think I try my best
User Infominer
by
3.3k points
14 votes
14 votes

An inverse function
f^(-1) is such that


f\left(f^(-1)(x)\right) = f^(-1)(f(x)) = x

(a) Given
f(x) = x-3 and
g(x) = x+3, we have


f(g(x)) = f(x+3) = (x+3)-3 = x

and


g(f(x)) = g(x-3) = (x-3)+3 = x

so
f and
g are indeed inverses of one another.

(b) Given
f(x)=\frac1{4x} and
g(x)=-\frac1{4x}, we have


f(g(x)) = f\left(-\frac1{4x}\right) = \frac1{4\left(-\frac1{4x}\right)} = -\frac1{\frac1x} = -x \\eq x

so
f and
g are not inverses of one another.

User Tom Johnson
by
3.1k points