i'm trying calculate/plot fourier series of function in matlab. function
f(t) = 1-cos(t) [-pi,0] , f(t) = t/pi [0,pi].
i need find how many terms in series needed approximate original signal 99% of average energy. i'm trying use while loop it, can't seem comparison condition work. full code below.
clear n = 0; syms t; f1 = 1-cos(t); f2 = t/pi; e1 = int((abs(f1))^2,-pi,0); e2 = int((abs(f2))^2, 0, pi); e_av = (1/(2*pi)) * (e1 + e2); k = 1 : 11 c_n(k) = subs((1/(2*pi)) * (int((f1 * exp(-1j*n*2*pi*t)),-pi,0) + int((f2 * exp(-1j*n*2*pi*t)), 0, pi))); n=n+1; end sum = c_n(1).^2; = 2; while (sum < 0.9075) sum = sum + 2*c_n(i).^2; = i+1; end display(i) display(sum) the 0.9075 99% of e_av.
i kind of understand error means, i'm assuming matlab reads sum symbolic variable reason, , can't compare sym logical. when first defined, sum = c_n(1).^2;, it's value, not sym (c_n(1) cn0, first fourier coefficient). symbolic variable t somehow carrying on c_n after being integrated out? appreciated.
thankyou
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