f_1(x) = (sin((π * x)) / ((π * x)))^(2)
x_0 = 1 (slider from -5 to 5, step 0.1)
f_2(x) = (sin((π * (x - x_0))) / ((π * (x - x_0))))^(2)
f_t(x) = f_1(x) + f_2(x)