Hi,

I'm trying to resolve a problem in physics (movement of a particle in a magnetic field) and plot it. I need initial conditions on both (x,y) and (x',y') but when I'm trying to put the four conditions in the initial list of DEplot, a mysterious mistake arises :

Error, (in dsolve/numeric/process_input) invalid specification of initial conditions, got {0 = 0, 0 = 1}

But here is my worksheet :