# Tagged Questions

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### find the cube roots of -8i and plot them on a plane

I can't figure out the angle of this equation. I set it up like this: $$z^3=0-8i$$ I find that the r value is 2, but when I try to find the angle I'm stuck. I can't divide by 0, so where did I go ...
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### On a certain series of complex numbers

Is it possible that the above infinite series is equal to ?
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### Alternative definition of complex number, showing it is equivalent to the tradidional one.

The author of a book makes an alternative definition of the complex numbers, later he shows that this definition is equivalent to the ordinary definition where we define $i^2=-1$. Here is his ...
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### Complex numbers quesiton

z1 z2 z3 are three points on the gauss plane and create a triangle ; it is known that z1 = 3sqrt3 +3i, z2 = z1/cis240 deg , z3 = z2cis60 deg . given this data show that the triange is a staright ...
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### Laplace transform of and impulse sampled function using “frequency” convolution

This is a long question, but assume we have this: The book uses the frequency convolution theorem to solve this problem. To solve the integral, it uses a contour + residue theorem to solve it. The ...
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### How is this computed?

$\left| 1-e^{-is\lambda} \right|^2 = 2 (1-cos\lambda s)$ where $i=\sqrt{-1}$ I don't know how to work with $i$. Thanks
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