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# Brouwer's Fixed Point Theorem

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Prove that if D is the closed disc |x| =< 1 in R2, then any map f E C2[D --> D]
has a fixed point: f(x) = x. The proof is by contradiction, and uses Stokes theorem. Follow the steps outlined below.
(1) Define a new map F(x) = ...
.....
Show that F has no fixed points if r is small enough.
(2) Draw the ray from F(x) to x (these are distinct) and note where it cuts the circle C : |x| = 1. This point G(x) = (cos , sin ) depends smoothly on x, i.e.  2 C2(D); moreover, it reduces to the identity on C.
(3) Now compute
....
(4) Explain why the above is a contradiction?
Since this is an analysis problem, please be sure to be rigorous, and include as much detail as possible so that I can understand. Please also state if you are making use of some fact or theorem. Thanks!