Principal root of a Complex Number

DEMJ
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Homework Statement


Find all the roots in rectangular coordinates, exhibit them as vertices of certain squares, and point out which is the principal root.


The Attempt at a Solution



The problem is (-8 -8\sqrt{3}i)^{\frac{1}{4}} and I found the four roots easily to be

\pm(\sqrt{3} - i), \pm(1 + \sqrt{3}i). So when it says to exhibit them as vertices of certain squares does this mean I should just graph the four points? and it should be a square.

Also as for which point is the principal root I have no clue. I am guessing it has something to do with principal argument but I am having trouble finding much information on principal roots.
 
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For any non-zero complex number, its fourth roots are arranged on the vertices of a square. You are being asked to verify this for the given number.

If I'm not mistaken, the principal root is the root whose standardized argument is least.

--Elucidus
 
Prove $$\int\limits_0^{\sqrt2/4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx = \frac{\pi^2}{8}.$$ Let $$I = \int\limits_0^{\sqrt 2 / 4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx. \tag{1}$$ The representation integral of ##\arcsin## is $$\arcsin u = \int\limits_{0}^{1} \frac{\mathrm dt}{\sqrt{1-t^2}}, \qquad 0 \leqslant u \leqslant 1.$$ Plugging identity above into ##(1)## with ##u...
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