I am very very new in Mathematica. I am deriving equations for a system of pendulums using the Lagrange function. As you can see, I wrote down the equations of the coordinates of the pendulums, and the output then is the Lagrange function, but I do not quite understand it. Can someone introduce me?
What is your question specifically? Is it about code or physics? Per forum rules you need to be detailed about what you are asking:
It looks like you have some variables already defined as interpolating functions from a previous evaluation. Try restarting the kernel reevaluating.
Thanks for your answer, I reinstalled Mathematica and now it works.
When defining a function use patterns in the left-hand side:
o[t_] = sec[(b''[t]*L*M)/(k1*r)];
gamma[t_] = (a''[t]*L*M)/(k2*cos[o[t]]);
x1[t_] = (b''[t]*L*M)/k1;
y1[t_] = r*sin[o[t]] + gamma[t];
x2[t_] = L*(sin[a[t]]*cos[b[t]]) + x1;
y2[t_] = L*(sin[a[t]]*sin[b[t]]) + y1;
z2[t_] = -L*cos[a[t]];
Also, you probably have to write x1[t] instead of simply x1 in the right-hand side. Functions like sine and cosine must be written with capital initials: Sin, Cos, Sec etc.