Then, Sunday

So I asked myself the question, how are complex
numbers useful in real world situation? On reflection -
and with a little help from the internet - now I know!
Anything other than geometry issues that gets tackled
in vector space is a complex problem. Awesome!

http://visualizingmathsandphysics.blogspot.com/2013/06/complex-numbers.html

https://www.theguardian.com/notesandqueries/query/0,5753,-18864,00.html

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Frm the context of algebra, there is an actual test that tells
one when one needs to use complex numbers. For roots
ie x-interceps of the equation, when the discriminant is less
than 0.

This first equation doesn't have whole roots, but it does intercept the x-axis.

This equation does not, as the discriminant test yields a negative value.

For a full walk-through:

http://www.biology.arizona.edu/biomath/tutorials/Quadratic/Roots.html

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