Show that the magnetic vector potential for two long, straight, parallel wires carrying the same current, I, in opposite directions is given by: A→ = μ 0I / 2π ln(r1/r2)n^
where r2 and r1 are the distances from the field point to the wires, and n^ is a unit vector parallel to the wires.

Which statement is true? a. kepler's laws apply only to the motion of earth. b. kepler's laws can be used to predict eclipses. c. kepler's laws are true for a central force that is directly proportional to distance. d. kepler's laws can be deduced from newton's laws of motion and gravity.