x=var('x')
a=3 #LET US SUPPOSE
e=2/a
b=sqrt(a^2*(1-e^2))
y=sqrt(b^2*(1-x^2/a^2))
plot(y,(x,-a,a),color="blue")+plot(-y,(x,-a,a),color="blue")

SageDays/Kreyszig-1.8-1 (last edited 2010-08-11 10:38:35 by msunyuma)