Original file(SVG file, nominally 575 × 449 pixels, file size: 352 KB)

## Summary

Description
English: A saddle point, on the graph of the function ${\displaystyle f(x,y)={\frac {1}{2}}\cos \left({\frac {x}{2}}\right)+\sin \left({\frac {y}{4}}\right)}$
Español: Punto de silla en la función ${\displaystyle f(x,y)={\frac {1}{2}}\cos \left({\frac {x}{2}}\right)+\sin \left({\frac {y}{4}}\right)}$
Date
Source Own work
Author Nicoguaro
SVG development
 This vector image was created with Matplotlib.

## Python

import numpy as np
from numpy import pi, sin, cos
from mpl_toolkits.mplot3d import Axes3D
import matplotlib.pyplot as plt

fig = plt.figure()
plot_args = {'rstride': 1, 'cstride': 1, 'cmap':"Blues_r",
'linewidth': 0.4, 'antialiased': True,
'vmin': -1.5, 'vmax': 1.5}

x, y = np.mgrid[-6:2:31j, -2:6:31j]*pi
z = 0.5*cos(x/2) + sin(y/4)

ax.plot_surface(x, y/2, z, **plot_args)
ax.plot([-2*pi], [pi], [0.5], marker='o', mfc='w', mec='k', mew=1)
ax.view_init(azim=-60, elev=45)
ax.set_xlim(-6*pi, 2*pi)
ax.set_ylim(-pi, 3*pi)
ax.set_zlim(-2, 2)
plt.xticks([-6*pi, -2*pi, 2*pi],
[r"$-6\pi$", r"$-2\pi$", r"$2\pi$"])
plt.yticks([-pi, pi, 3*pi],
[r"$-2\pi$", r"$2\pi$", r"$6\pi$"])
ax.set_zticks([-2, 0, 2])
ax.set_zticklabels([r"$-2$", r"$0$", r"$2$"])
ax.w_xaxis.set_pane_color((1.0, 1.0, 1.0, 0.0))
ax.w_yaxis.set_pane_color((1.0, 1.0, 1.0, 0.0))
ax.w_zaxis.set_pane_color((1.0, 1.0, 1.0, 0.0))
ax.set_xlabel(r"$x$", fontsize=18)
ax.set_ylabel(r"$y$", fontsize=18)
ax.set_zlabel(r"$z$", fontsize=18)
plt.show()


## Licensing

I, the copyright holder of this work, hereby publish it under the following license:
 This file is licensed under the Creative Commons Attribution 4.0 International license. You are free: to share – to copy, distribute and transmit the work to remix – to adapt the work Under the following conditions: attribution – You must attribute the work in the manner specified by the author or licensor (but not in any way that suggests that they endorse you or your use of the work).

## File history

Click on a date/time to view the file as it appeared at that time.

Date/TimeThumbnailDimensionsUserComment
current00:52, 18 May 2016575 × 449 (352 KB)NicoguaroUser created page with UploadWizard
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## Global file usage

The following other wikis use this file:

• Usage on es.wikipedia.org