math
posted by Kennedy .
which of the following functions have a inverse?
f(x)=ab.solute value of x.
f(x)=x^3
f(x)=x^4
f(x)=x^3
f(x)=x^4,xless then or equal 0.
how do i know if they have an inverser, can someone please explain:) thanks for your time YOOO

x^3 has an inverse, as does x^4 x<=0
Why? The others do not have a one for one mapping from x to one f(x).
for instance, x^4 f(sqrt2)=f(sqrt2)
http://www.uncwil.edu/courses/mat111hb/functions/inverse/inverse.html#sec1