(ASAP)why symsum can not calculation?????

t = (-2:0.5:2);
a=1;
x1=1/2 + symsum((1/2)*(sinc(a/2))*cos(2*pi*a*t)/4,a,1,inf);
plot(t,x1)

[Star Strider]

It cannot be calcualted because you are not using symbolic calculations.

Perhaps this —

syms a t 
% t = sym(-2:0.5:2);
% a=1;
x1(t) = 1/2 + symsum((1/2)*(sinc(a/2))*cos(2*pi*a*t/4),a,1,inf);
x1 =  simplify(x1, 500)

x1(t) = 

Check = vpa(x1(-2:0.5:2))

Check = 

figure
fplot(x1, [-2 2])
grid
axis([-3 3  0 1])

Warning: Error updating FunctionLine.

The following error was reported evaluating the function in FunctionLine update: Unable to convert expression containing remaining symbolic function calls into double array. Argument must be expression that evaluates to number.

I corrected the ‘x1(t)’ expression to match the image.

.

Answer 1

[Torsten]

t = -2:0.1:2;
a = 1;
N = 60;
n = (1:N).'; 
f = sinc(n/2).*cos(2*pi*a*n.*t/4);
s = 0.5 + sum(f,1);
plot(t,s)

[Dyuman Joshi]

Different output for the original summation (1 to Inf)

And if the number of elements of t are increased, the code does not run in the time limit here.

t = -2:2;
syms a
x1 = 1/2 + symsum((1/2)*(sinc(a/2))*cos(2*pi*a*t)/4,a,1,Inf);
plot(t,x1)