Coefficent Matrix in Python - Group elements -

i have obtatained matrix in python using sympy:

> matrix([[-theta*l*m2*omega**2*cos(omega*t) + x*k*cos(omega*t) - > x*omega**2*(m1 + m2)*cos(omega*t)], [theta*g*cos(omega*t) - > theta*l*omega**2*cos(omega*t) - x*omega**2*cos(omega*t)]]) 

i need find expression like:

[coefficient matrix]*(unknowns vectors) 

where (unknowns vector) is:

matrix([[x],[theta]]). 

i tried use solve, simplify , collect sympy without success (i can errors or [] return).

take jacobian:

in [16]: a.jacobian(matrix([x, theta])) out[16]: ⎡              2                                2              ⎤ ⎢k⋅cos(ω⋅t) - ω ⋅(m₁ + m₂)⋅cos(ω⋅t)      -l⋅m₂⋅ω ⋅cos(ω⋅t)     ⎥ ⎢                                                              ⎥ ⎢             2                                      2         ⎥ ⎣           -ω ⋅cos(ω⋅t)             g⋅cos(ω⋅t) - l⋅ω ⋅cos(ω⋅t)⎦  in [17]: a.jacobian(matrix([x, theta]))*matrix([x, theta]) out[17]: ⎡              2              ⎛              2                   ⎞⎤ ⎢- theta⋅l⋅m₂⋅ω ⋅cos(ω⋅t) + x⋅⎝k⋅cos(ω⋅t) - ω ⋅(m₁ + m₂)⋅cos(ω⋅t)⎠⎥ ⎢                                                                 ⎥ ⎢             ⎛                2         ⎞      2                 ⎥ ⎣       theta⋅⎝g⋅cos(ω⋅t) - l⋅ω ⋅cos(ω⋅t)⎠ - x⋅ω ⋅cos(ω⋅t)        ⎦  in [22]: out[22]: ⎡              2                              2                   ⎤ ⎢- theta⋅l⋅m₂⋅ω ⋅cos(ω⋅t) + x⋅k⋅cos(ω⋅t) - x⋅ω ⋅(m₁ + m₂)⋅cos(ω⋅t)⎥ ⎢                                                                 ⎥ ⎢                                 2               2               ⎥ ⎣     theta⋅g⋅cos(ω⋅t) - theta⋅l⋅ω ⋅cos(ω⋅t) - x⋅ω ⋅cos(ω⋅t)      ⎦ 

by way, if use theta or theta (not uppercase), sympy print actual greek letter theta:

in [24]: symbols('theta') out[24]: θ