#Example 3, page no 5
var('x')
y = function('y', x)
f(x) = desolve(diff(y, x) - cos(x), y)
show(f(x))
P = []
for i in range(-3, 3, 1):

    P.append(plot(f(x).subs(c=i), (x, -2*pi, 2*pi), color='blue'))
    show(plot(P))