Thread: Most Interesting Equation

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

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

Total area of your skin:
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

Originally Posted by HallsofIvy

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

What is this equation used for?

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.

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.