How to plot satellite orbit around the earth

Can someone show me a simple code to plot the trajectory of a satelittle based on the semi-major axis, a and radius.

[James Tursa]

Plot an ellipse directly. Plot the results of an ode45( ) integration? Plot the results of your own Euler or Modified Euler integration? Can you give more details what the assignment is?

[Caroline Kenemer]

give i) the type of orbit trajectory (circle, ellipse, parabola, or hyperbola), ii)the semimajor axis (a), and iii) plot the trajectory in Matlab or equivalentsoftware. In each plot, place the perigee on the right hand side, set the axislimits to +/- 2.5 Earth radii (use Earth radiusRe= 6378 km), and usetheaxis imagecommand to obtain a square aspect ratio (this will correctlydisplay the shape of the trajectory). Use thegridcommand to turn ona numeric grid on your plot. Use enough points in Matlab to make thetrajectory easily visible (you might want to write a Matlab script to dothis). Draw the radius of the Earth on the plot as a circle withr= 1 Earthradius (you can do this manually or Matlab do it for you).

I found the type of trajectory and the semi-major axis but do not know how to plot it.