Definition of rolle's theorem in English English dictionary
A theorem stating that if a curve is continuous, has two x-intercepts, and has a tangent at every point between the intercepts, at least one of these tangents is parallel to the x-axis. Special case of the mean-value theorem of differential calculus. It states that if a continuous curve passes through the x-axis twice within a given interval and has a unique tangent line at every point of that interval, then somewhere between the two points of interception it has a tangent parallel to the x-axis