1. ## Most Interesting Equation

In your opinion, what is the most interesting equation in the world of math? What makes it interesting?

2. ## Re: Most Interesting Equation

$e^{ix}= cos(x)+ i sin(x)$

3. ## Re: Most Interesting Equation

SQRT(W * H) / 60, where W = weight in kg. and H = height in cm.

Much valuable time has been wasted regarding the above,
as you will notice here:
https://www.calculator.net/body-surf...alculator.html

4. ## Re: Most Interesting Equation

Originally Posted by HallsofIvy
$e^{ix}= cos(x)+ i sin(x)$
What is this equation used for?

5. ## Re: Most Interesting Equation

Originally Posted by harpazo
What is this equation used for?
Among other things it's the basis for representing sinusoidal signals with a non-zero phase shift as a complex exponential.

This makes certain calculations much more elegant.

You can Wiki Fourier Series which is one of the more powerful tools in the box.

6. ## Re: Most Interesting Equation

Originally Posted by romsek
Among other things it's the basis for representing sinusoidal signals with a non-zero phase shift as a complex exponential.

This makes certain calculations much more elegant.

You can Wiki Fourier Series which is one of the more powerful tools in the box.
I thank you for your reply but Fourier Series is too advanced for me at this time.