In a laterally insulated bar with the length of 1 , assume the following hold: ut=uxxu(x,0)={x0.25(1x)0x0.20.2x1u(0,t)=u(1,t)=0 a) Apply the explicit method with h=0.2,k=0.01 for 5 steps. b) Apply Crank-Nicholson method with h=0.2 in 2 steps. Compare with (a)