Hi all, I am having trouble numerically integrating a function using Maple 10. Here is a bit of background on the problem: This problem is asking for two plots, one of the velocity of a sounding rocket with respect to time, and the other being the height of the sounding rocket with respect to time. Gravity and drag act on this rocket. I have the following equations: density as a function of altitude drag coefficient as a function of mach number mach number as a function of velocity drag as a function of drag coefficient thrust as a function of mass flowrate and exhaust velocity mass as a function of time This problem asks to create these plots for various values of mass flowrate that I am supposed to set myself (2 kg/s, 2.1 kg/s, 2.2...etc). The known constants that I have are the following: specific impulse exhaust velocity initial mass initial velocity initial height initial density After inputting everything into maple, I come up with this differential equation: sys1 := [diff(v(t),t) = (thrust-drag-mass*9.81)/mass, diff(y(t),t) = v(t)]; I am not great with maple, so I am not sure if this is even the correct syntax. In my attempt to solve the differential equation, I tried this command: sol1 := dsolve(sys1, numeric, v(0)=0, y(0)=0); Unfortunately, this gives me the following error: Error, (in dsolve/numeric/type_check) insufficient initial/boundary value information for procedure defined problem Any suggestions as to what may be causing the problem here? If necessary, I can post my entire maple file if more detail is needed. Thanks in advance.