# A calculus problem by Archit Tripathi

Calculus Level 5

If $$f$$ is a differentiable function [other than $$(f(x) = x)$$] which satisfies:

$$f(x+f(y)+xf(y)) = y+f(x)+yf(x)$$ for all real $$x, \ y \ne -1$$, then find the value of $$4034[1+f(2016)].$$

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