If the charge of a particle changes from 2C TO -2C, what happens to the force exerted on that particle?

Determine the maximum r-value of the polar equation r =3+3 cos 0

Could someone me find the answer to this problem.

As seen in a us weather map, the h (or high) and l (or low) symbols indicate regions where surface air pressures are high or low, respectively, compared to surrounding areas. an h is plotted where the air pressure is highest and an l is plotted where the air pressure is lowest. proceeding outward and away from the center of a high pressure system, the air pressure "