細長く表示します。
(参考)大学入試問題で現れる世界遺産
https://qiita.com/kazukiii/items/bbb55f873730b6e31f2b

from sympy import *
import matplotlib.pyplot as plt
var('x')
F  = x**4 - x**2 + 6
G = cos(2 * pi * x) / 2 + 7 / 2
H = 12 / (abs(x) + 1)
p1 = plot(F, (x, -1, 1), show=False)
p2 = plot(G, (x, -2, 2), show=False)
p4 = plot(H, (x, -8,-1), show=False)
p3 = plot(H, (x,  1 ,8), show=False)
p1.extend(p2)
p1.extend(p3)
p1.extend(p4)
# p1.gca().set_aspect('equal')
p1.show()
#   File "C:/Users/xxx/.PyCharmCE2018.2/config/scratches/scratch_30.py", line 85, in <module>
#     p1.gca().set_aspect('equal')
# AttributeError: 'Plot' object has no attribute 'gca'