#prob 42
t=var('t') # t represents the time
W,B,m,k=var('W B m k')
v=function('v',t)
W=2254;B=2090;k=.637;m=1
diffeq=m*diff(v,t)-W+B+k*v
sol=desolve(diffeq,[v,t],ics=(0,2))
sol
plot(sol,(t,0,20))