var('x')
x0 = 0
k=1
f = x*exp(-x^2)
p = plot(f,0,2*pi, thickness=2)
c = 1/pi
orden=10
alpha=[(n,c*numerical_integral(f*sin(x*n/2),0,2*pi)[0] ) for n in range(1,orden)]
@interact
def _(tiempo = (0.1*j for j in (0..10)) ):
ft = sum( a*sin(x*n/2)*exp(-k*(n/2)^2*tiempo) for n,a in alpha)
pt = plot(ft, 0, 2*pi, color='green', thickness=2)
show( p + pt, ymin = -.2)
