Finding the magnitude of an expression

Supposing that x can be expressed as a function of t as follows how can its magnitude be found using Matlab? For example, is there some way to simplify the expression as for example A*cos(wt+b) + B * exp(-0.25t)*sin(wt+c) so the magnitude would be sqrt(A^2+B^2) if this were possible?

syms t 
x = 0.113*sin(3.0*t) - 0.125*cos(3.0*t) + 0.125*exp(-0.25*t)*cos(3.15*t) - 0.0977*exp(-0.25*t)*sin(3.15*t)
  

[KSSV]

How the magnitude of the given function will be sqrt(A^2+B^2) ? Is it a complex number?

Answer 1

[David Hill]

I would not use symbolic unless you need to.

x = @(t)0.113*sin(3.0*t) - 0.125*cos(3.0*t) + 0.125*exp(-0.25*t).*cos(3.15*t) - 0.0977*exp(-0.25*t).*sin(3.15*t);
t=0:.01:2*pi;
plot(t,x(t));