What is the inverse function of #y= -3 #?

1 Answer
Jim H
Sep 30, 2015

The function #f(x) =-3# does not have an inverse function.

Explanation:

A function #f# has an inverse if we can determine, without saying "or" from the #y# value, what the #x# value was.

We would need to be able answe with ceratinty, "Waht one number MUST have been the input (the #x# value) have been, if the output (the #y# value was this?.

Clearly, in this example, knowing the #y# value (#3#) does NOT tell me the ONE #x# value we must have used. #x# could have been anything.

Compare this to the function #f(x) = 2x+1#. If you tell me the output, I can work backwards to the input without saying "OR". (Functions do not say "OR". The give one answer, never two or more.)

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