import matplotlib.pyplot as plt
import math

x = [0]
y = [0]
u = [1]

h = 0.01

i = 0
while i <= 20000:
    x.append(x[i] + h)
    y.append(y[i] + h * u[i])
    u.append(u[i] + h * (- 0.64 * math.sin(y[i])))
    i += 1

plt.plot(y, u)
plt.show()