How do you find the inverse of #f(x) =1/(4x+7)# and is it a function?

1 Answer
Apr 16, 2016

If #y = f(x) = 1/(4x + 7), f^(-1)(y)=(1-7y)/(4y)=x# is a function.
In simple words, if y is a function of x, inversely, x is a function of y. .

Explanation:

If y = f(x), the inverse relation is #x=f^(-1)(y)#.

The mapping, either way, is #1-1, or many-1, or 1-many#

In f(x) = arc sin (x), it is 1-many mapping.

In f(x) = sin x, it is many-1 mapping.

Yet, by definition,

# f^(-!)(f(x)) = x and f( f^(-1)(y))=y#.

Here, solving for x, the inverse relation is #x = (1-7y)/(4y)#.
This is 1-1 mapping. .