How do you find #f^-1(x)# given #f(x)=-1/x^2#?

1 Answer
Apr 1, 2018

#f(x)^-1=+-sqrt(-1/x)#

Explanation:

You substitute the x values for the y values

#x=-1/y^2#

Then we rearrange for y

#xy^2=-1#

#y^2=-1/x#

#y=+-sqrt(-1/x)#

Such a function doesn't exist as you can't have a negative root on the #RR# plane. Also it fails the function test as you have two x values corresponding to 1 y value.