Question
A student writes, "The inverse of y = -√(x+2) is y = x^2 - 2." Why is this statement false?
I don't understand how it isnt the inverse. The textbook says that changing the domain will make it the inverse? Wouldn't that only make it a function?
I don't understand how it isnt the inverse. The textbook says that changing the domain will make it the inverse? Wouldn't that only make it a function?
Answers
Steve
You need f(f^-1(x)) = x
-√(x^2-2 + 2) = -√(x^2) = -x
this fails because x^2 is not one-to-one
-√(x^2-2 + 2) = -√(x^2) = -x
this fails because x^2 is not one-to-one