How make symbolic variables to a power equal to zero

Hi,

I'm calculating inertia using thin strucuter theory. I have all of my components of inertial set as an symbolic array.

for example:

Iy_ = [16*t^3 / a, a^2 * t]

However, I need to equate any element in the array to 0 if the variable t is to an power greater than 1. So t^2, t^3, ... would equal zero where as t would remain as t.

Is there any convineint way to do this in MATLAB 2020a?

Thanks in advanced.

Answer 1

[Uday Pradhan]

Hello,

I believe the below information will be helpful:

syms t;
sympol = 10 * t^2; 
deg = numel(sym2poly(sympol)) - 1; %sym2poly extracts vector of all numeric coefficients, including zeros, from symbolic polynomial
if deg > 1
    % evaluate sympol to 0
end

This way you can get the degree of the symbolic polynomial and then do the required computations. Documentation of sym2pol is here.

Answer 2

[Paul]

syms a t
Iy = [16*t^3 / a, a^2 * t]

Iy = 

Iy(polynomialDegree(Iy,t)>1) = sym(0)

Iy =