Im only quite confident about quadratic equations and as far as I've heard, extreme values are maxima and minima.
Also,I've heard that a polynomial of degree n has at most (n-1) extreme value points.
My confusion begins here, for example for quadratic, the parabola always tends to +/- inf and also, There is its vertex which is an extreme value point. But as i browse the web, nobody counts the inf point as an extreme value.
I'm new to this my concepts might be wrong. Please help me with this and thank you in advance.
Notice that the number of local minima and maxima of a polynomial of degree $n$ is $(n-1)$.
This is because local minima and maxima can only be at points where the first derivative of the polynomial is 0.