Our school is using a new on line Algebra 2 book this fall. The algebra teachers noticed that function notation was used for inverses even if the inverse was not a function. For instance, if the function was f(x) = x^2, the inverse was noted as f^-1(x) = +/_ square root (x). We have always taught that if the inverse is not a function, then you could not use inverse function notation on the inverse equations. Is this acceptable notation? Thanks for any help.