A value x is a fixed point of a function f if and only if f(x) = x.
1 is a fixed point of x 2 {\displaystyle x^{2}} because 1 2 = 1 {\displaystyle 1^{2}=1} . Some functions do not have fixed points. For example x + 1 {\displaystyle x+1} does not have one because x + 1 {\displaystyle x+1} is never equal to x.