Newton's law of gravitation states that the force of F of attraction between tow particles having masses m and M is given by F = (gmM)/(s^2) for a constant g and the distance s between the particles. If s = 20cm, use differentials to approximate the change in s that will increase F by 10%.
Most of what I am about to say is not technically correct but it will help you understand....since a derivative is measuring slope you have the derivative is ...therefore ...so you take the derivative so you can get your changes in x and y...now that you have that seperate...so you are trying to find the change in s( ) that makes F change 10%...make sense?