Rolle's theorem in Portuguese

(calculus) The theorem that any real-valued differentiable function that attains equal values at two distinct points must have a point somewhere between them where the first derivative (the slope of the tangent line to the graph of the function) is zero. In mathematical terms, if f : \mathbb{R} \rightarrow \mathbb{R} is differentiable on (a,b) and f(a)=f(b) then \exists c \in (a,b) : f'(c)=0.