An unmyelinated axon has the following properties: radius of 0.25 mm, membrane capacitance of 0.01 F/m^2 , resistance per unit length along the axon of 2x10^6 omega/m, and propagation velocity of 20 m/s. The propagating pulse passes an observer at x=0. The peak of the pulse can be approximated by a parabola, v(t)=20 (1 - 10t^2), where v is the mV and t is in ms. (a) find the current along at x=0, t=0 (b) find the membrane current per unit area at x=0, t=0