I have created this topic before: How to Add another subplot to show Solid of Revolution toward x-axis?
I want to plot the solid from a curve 3 + 2x - x^2 that is revolved about:
a. the x-axis
b. the y-axis
c. the line y = -1
d. the line x = 4
this is my MWE (the problem is to find the inverse of 3 + 2x - x^2 is not something easy thus I have no idea how to make this code works):
# Compare the plot at xy axis with the solid of revolution toward x and y axis
# For function x=(y)^(3/2)
import matplotlib.pyplot as plt
import numpy as np
n = 100
fig = plt.figure(figsize=(14, 7))
ax1 = fig.add_subplot(221)
ax2 = fig.add_subplot(222, projection='3d')
ax3 = fig.add_subplot(223)
ax4 = fig.add_subplot(224, projection='3d')
y = np.linspace(0, 9, n)
x = (y) ** (3 / 2)
t = np.linspace(0, np.pi * 2, n)
xn = np.outer(x, np.cos(t))
yn = np.outer(x, np.sin(t))
zn = np.zeros_like(xn)
for i in range(len(x)):
zn[i:i + 1, :] = np.full_like(zn[0, :], y[i])
ax1.plot(x, y)
ax1.set_title("$f(x)$")
ax2.plot_surface(xn, yn, zn)
ax2.set_title("$f(x)$: Revolution around $y$")
# find the inverse of the function
x_inverse = y
y_inverse = np.power(x_inverse, 3 / 2)
xn_inverse = np.outer(x_inverse, np.cos(t))
yn_inverse = np.outer(x_inverse, np.sin(t))
zn_inverse = np.zeros_like(xn_inverse)
for i in range(len(x_inverse)):
zn_inverse[i:i + 1, :] = np.full_like(zn_inverse[0, :], y_inverse[i])
ax3.plot(x_inverse, y_inverse)
ax3.set_title("Inverse of $f(x)$")
ax4.plot_surface(xn_inverse, yn_inverse, zn_inverse)
ax4.set_title("$f(x)$: Revolution around $x$")
plt.tight_layout()
plt.show()
