Hi, I am completely stuck on this problem that has been given to us. I must solve a set of 2nd order differential equations using Euler's method. It is for a geosychronous orbit of a satellite, meaning the orbit is circular and the velocity vector is perpendicular to the radius vector (r.V=0). The equations are: d2x/dt2=-k2x/r3 and d2y/dt2=-k2y/r3 k^2,r and V are all given. My first step was to set up sets of ode's to solve. for the first equation we have, let y1=x and y2=dy1/dt hence, dy2/dt= -k2y1/r3 and for the second, let y3=y and y4=dy3/dt hence, dy4/dt= -k2y3/r3 which I think is correct. Now I have to pass this into a matlab function which uses eulers method. But I have no idea how to implement it. my main problem at the moment is that I do not know what to use as my initial y1,2,3,4 values in the function vector. Can any one help?