How do i multiply two functions

Hello, i have an assignment for school in which i need to plot the z function, where z needs to be:

z=x1*x2,
x1=29*t^2-165*t+420
x2=x2=symsum((-1)^k*dirac(t-24*k), k, -100, 100),

and t=0:1:24*25 (to represent 25 periods of x2).

But when i try to multiply x1 with x2, i get this error:

Error using symengine, The dimensions do not match.

What can i do?

[Jan]

Please post the code you have tried for this multiplication. Obviously it contains an error, but if the readers do not know, how you have tried this, they have to guess.

I have formatted your code this time using the "{} Code" button.

Answer 1

[Birdman]

Try this:

syms t k
x1=29*t^2-165*t+420 
x2=symsum((-1)^k*dirac(t-24*k), k, -100, 100)
tt=subs(t,0:1:24*25);
x1=subs(x1,t,tt)
x2=subs(x2,t,tt)
z=x1.*x2;