Let P ∈ R [ X ] {\displaystyle {}P\in \mathbb {R} [X]} be a polynomial of degree d ≥ 1 {\displaystyle {}d\geq 1} , P ≠ X {\displaystyle {}P\neq X} . Show that P {\displaystyle {}P} has at most d {\displaystyle {}d} fixed points.
![{\displaystyle {}P\in \mathbb {R} [X]}](https://wikimedia.org/api/rest_v1/media/math/render/svg/9bf6bcf64e16c3ac6b30ecd6577e72648ab2325a)
