I am trying to solve a system of differential equations.

eqn = {
y''[t] == (39/10000 +
58/10000/(1 +
Exp[(Sqrt[(Cos[10*2*Pi/360])^2 + y'[t]^2 + z'[t]^2] - 35)/
5]))*Sqrt[(Cos[10*2*Pi/360])^2 + y'[t]^2 + z'[t]^2]*y'[t],
z''[t] == (39/10000 +
58/10000/(1 +
Exp[(Sqrt[(Cos[10*2*Pi/360])^2 + y'[t]^2 + z'[t]^2] - 35)/
5]))*Sqrt[(Cos[10*2*Pi/360])^2 + y'[t]^2 + z'[t]^2]*
z'[t] + 41/100000 *(30*(Cos[10*2*Pi/360])), y'[0] == 0,
z'[0] == 40*Sin[10*2*Pi/360], y[0] == 0, z[0] == 3/2}

sol = DSolve[eqn, {y[t], z[t]}, t]


However this does not give me any solution. Only oupout is my input. I cannot seem to figure out what I did wrong...

Any ideas?

Thank you very much!

• Have you tried solving it with NDSolve ? – Sektor Jun 30 '15 at 15:03
• I have to get an analytical solution :/ – 13Thison13 Jun 30 '15 at 15:08
• I believe Sektor was hinting that an analytical solution to your non-linear ODE probably does not exist. Perhaps math.stackexchange.com could help you determine if one does. – Ian Jun 30 '15 at 17:39