 Intel's Ronler Acres Plant

# Pergelator

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## Tuesday, January 2, 2018

### Desmos Graphing Calculator

I've been hanging out at Quora lately. A fair number of math problems show up there. Many of them are inane, like 'What is 2+2?", or "What is 3+3 x 3?".* But some advanced ones show up as well. Some of them are really ugly, I've never seen the like before, don't know what they're good for, or why anyone would care, but they make me curious so I've taken to plotting them on the Desmos Graphing Calculator.  It would be nice if you could simply copy the equation from Quora and then paste in Desmos. You can, but it doesn't translate properly, so you have to go in and fiddle with it enough for Desmos to understand it. Plus sometimes the equation (or expression) you get from Quora is missing something, or didn't get entered properly, so you have to muck with it to get anything graphable.

The equation for the Middle Green Circle on the graph comes from this question on Quora.

Outer Orange circle    x^{2\ }+\ y^2\ =\ 16
Middle Green circle    e^{\left(y^2\ +\ x^2\ \right)^{.5}}\ =\ 16
Inner Orange circle    e^{.5\left(y^2\ +\ x^2\ \right)}\ =\ 16

The original equation from Quora.

# f(x,y) = e^sqrt (x^2+y^2)

Mucking about with above equation and then typing Ctrl-Z causes the graph above to be redrawn. Actually, it doesn't matter what you were doing before, if you have done anything at all in Blogger's Editor, Ctrl-Z (Undo) causes the graph to be redrawn.

Taking the Middle Green Circle and changing it to a function gives us this
f(x,y)=e^{(x^2+y^2)^{.5}}
but Desmos doesn't know how to graph it.

Note that I have replaced the call to sqrt with an exponent. Desmos treats sqrt as four variables (s, q, r & t) being multiplied together.

Also capital X and capital Y mean something special, so don't use them until you figure out they do.

This post started as a test to see if I could copy and paste the equations, but I can see it's expanded a bit.