Electrostatic Force. The magnitude of the electrostatic force between two point charges Q and q of the same sign is given by F(x)=kQq / x^2 where x is the distance (measured in meters) between the charges and k=9⋅10^9 Nm^2 / C^2 is a physical constant (C stands for coulomb, the unit of charge; N stands for newton, the unit of force). For two identical charges with Q=q= 2 C, what is the instantaneous rate of change of the force at a separation of x= 0.005 m?

Please show work (if you can).