(12 points) In a two-dimensional world, suppose that the gravitational force between mass m and
mass M is given by
F(x,y)=(-mMGx)/((x^(2)+y^(2))^((3)/(2)))i+(-mMGy)/((x^(2)+y^(2))^((3)/(2)))j
where G is a constant and mass M is fixed at the origin. Show that F is a conservative force field.
Use this fact to compute the work \int_C F*dr done by the force field in moving the mass m along a
smooth curve C from (-3,4) to (1,0).