# Isn't the data insufficient?

Calculus Level 4

If $$f(x)$$ is a function satisfying $$f(x+25) + f(x) = 0$$ for all $$x \in \mathbb R$$ such that,

$\int_{b}^{c+b} f(x) \ dx$

is independent of $$b$$, then find the least positive value of $$c$$.

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