Calculating jacobian while using symbolic toolbox

Hello! I can't seem to find the answer to my problem so I figured that I'd ask it myself.

I am trying to calculate the jacobian based on symbolic variables as follows:

syms x(t) y(t) z(t) theta(t) phi(t) L

q = [x, y, z, theta, phi].';

dq = diff(q,t);

p1 = [x, y, z].';

dp1 = diff(p1, t);

p2 = [x + L*cos(theta),
      y + L*cos(phi),
      z + L*sin(theta) + L*sin(phi)];

dp2 = jacobian(p2, q)*dq;

I want to use it to module a system using Lagrange modelling.

The error message comes as follow:

Error using sym/jacobian (line 44)

Second argument must be a vector of variables.

Error in untitled (line 15)

dp2 = jacobian(p2, q)*dq;

Thanks in advance, Jakob

[Bjorn Gustavsson]

My (admittedly old) version of jacobian doesn't like the time-variations in the variables x, y, z, theta, phi. Perhaps you can work your way around it by calculating the jacobian for variables not depending on time and then substitute the time-varying ones after that?

[Walter Roberson]

You cannot (at all easily) differentiate with respect to a function, only with respect to a variable.

[Jakob Vinkås]

Okey, thank you for the answer.

[Bjorn Gustavsson]

Also: are you sure about the expression for p2? It seems suspicious to me.

[Walter Roberson]

In particular if you are working with polar coordinates then you would normally multiply two trig components rather than add them.