Hello,

I would like to plot z(x(t)) with the odeplot function.

For the moment, i manage to plot x(t) and z(t).

But i don't manage to plot z(x(t)) ?

My last code lign is wrong.

Can you help me for this plotting ?

Thanks a lot

Here my code :

M:=1;

1l:=1;

g:=9.81;

sys:=diff(z(t),t,t)=-1/z(t)*diff(x(t),t)^2-1/z(t)*diff(z(t),t)^2-x(t)/z(t)*diff(x(t),t,t),M*(-l^2/(x(t)*z(t)))*diff(x(t),t,t)=M*g-M*(-1/z(t)*diff(x(t),t)^2-1/z(t)*diff(z(t),t)^2);

Cinit:=D(x)(0)=0,x(0)=0.99999999,D(z)(0)=0,z(0)=sqrt(l^2-0.99999999^2); D(x)(0) = 0, x(0) = 0.99999999, D(z)(0) = 0, z(0) = 0.0001414213562

sol:=dsolve({sys,Cinit},numeric);

tx:=odeplot(sol,[t,x(t)],0..10,numpoints=200,color=blue,legend="x"):display(tx);

tz:=odeplot(sol,[t,z(t)],0..10,numpoints=200,color=blue,legend="z"):display(tz);

txz:=odeplot(sol,[x(t),z(x(t))],0..10,numpoints=200,color=blue,legend="z"):display(tz);(x)