…code, cg, electronics, 3d printing…

Time to get back to the basics.  I use trig at work, and at home in PyGame\Processing, but I like understanding the fundamentals of how it works.  So I sat down one afternoon and made up a “SohCahToa” PyGame program that really illustrates (to me at least)  what the values behind sine, cosine and tangent mean.  They are after all, ratios of the sides of a triangle.

• Windows executable.  Find the zipped version here:
  • http://www.akeric.com/python/sohCahToa01.zip
• The source code is online here, feel free to grab it:
  • http://www.akeric.com/python/sohCahToa01.py
  • I built it with Python 2.6.2 and PyGame 1.9.1, but nothing fancy is going on with either, so it should work with older versions.

So the mnemonic device is “Soh-Cah-Toa”, which means:

• Sine = Opposite / Hypotenuse
• Cosine = Adjacent / Hypotenuse
• Tangent = Opposite / Adjacent

I wanted a visual way to see this in action, and that’s what this little program does:

It plots a triangle defined by the opposite, adjacent, and hypotenuse sides.  As time goes by ‘degrees \ radians \ pi’ values increase, and the triangle changes.  The lengths of each side are plotted, and at the bottom, the math behind the sin, cos, and tan are shown in real-time.

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SoftPedia has added SohCahToa to their site as well:

http://mac.softpedia.com/get/Utilities/SohCahToa.shtml