Can I get help with this question please? I've calculated some of it and got up to a Mayer f function requirement but cannot workout where to go from here.

Let f(x) = x4- 8x2 . find the relativeextrema of this function using the second derivative test.

Suppose a diode consists of a cylindrical cathode with a radius of 6.200×10^−2 cm , mounted coaxially within a cylindrical anode with a radius of 0.5580 cm . the potential difference between the anode and cathode is 260 v . an electron leaves the surface of the cathode with zero initial speed (v initial=0). find its speed vfinal when it strikes the anode.

Anika asks eva to roll a basketball and then a bowling ball to her. which requires more force to roll, and why?