i keep getting syntax error please help

x_p = -0.3906sin(0.559t) + 156.25cos(0.559t); % steady-state motion

Answer 1

[Luca Ferro]

to multiply you have to use *.

Assuming you defined or sym t,

x_p = -0.3906*sin(0.559*t) + 156.25*cos(0.559*t);