a problem of using matrix exponential expm()

Hello everyone,

I have some problems with USE of matrix exponential expm(A) in MATLAB. The matrix A is a Symbol matrix, and the size is a 6*6 .

the matrix A is

When I used the following code, there is no result appears. If somebody can help me, it could be great.

Thank you

if true
  % code
syms w;         
A=[0,0,-31.42,0,3.611e-11,0; 0,0,-15.71,3.611e-11,0,0; 13.46,-6.732,0,0,0,1.032e-11; 2.538e13,4.685e13 - 2760.0*w^2,0,0,0,-6.732; 8.492e13 - 2760.0*w^2,2.538e13,0,0,0,13.46; 0,0,-2760.0*w^2,15.71,31.42,0];
expm(A)
end