import numpy  as np
import matplotlib.pyplot as plt

x = np.linspace(0, np.pi*4, 100)
y = np.cos(x) + np.sin(x)
xmin, xmax = 0, np.pi*4
ymin, ymax = -2, 2

fig, ax = plt.subplots()
ax.plot(x, y)

ax.set_xlim(xmin, xmax)
ax.set_ylim(ymin, ymax)
#ax.axis([xmin, xmax, ymin, ymax])  # x軸とy軸の両方の範囲をまとめて設定