Pre Calc help!!!

Question

What is the maximum number of extrema of the graph of the functions?

f(x) = 2x^5 + 4x^3 + 6x + 1

f(x) = -x^3 + 1

f(x) = 6x^2 + 4x

show work please!

Answer 1

The derivative of the 1st function is strictly positive; therefore no extrema.

The derivative of the 2nd function is -3x² while there might be an max or min, in fact there is a point of inflection with a horizontal tangent

In the 3rd there can be only one max or min.