Finite product of complex terms

Gazouille
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Can one hint me towards finding a general formula for

<br /> P_n = \prod_{x=0}^{n} \left( \sqrt{x} + i\right)<br />

I need a direction because now I'm stuck with it after having struggled to formulate it.

Either the real or imaginary part would be enough but i guess i won't get one without the other. I'm working out now the term to renorm the result, i'll post it asap, it's nothing complicated.

This current formulation I made up for a geometrical problem i have :).
It is to evaluate exactly a spiral that interpolates a sequence of vertices in orthogonal triangles that you would stitch together (by hypothenuse to the variable length side of the next). I can make a drawing if necessary.

I need to sum up angles for each triangle to get a polar coordinate of the n-th vertex. Hopefully evaluable through a simple continuous function to get the in-betweens aswell.

I started with trying to work in log space but what i naturally get is a sum of arc-cosinuses that i can't find an interpolating function for...

Thanks for any hint :)
 
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I guess you should use letters of the smaller case, i.e. , and not , for the LATEX to be displayed.
 
yes i thought so, i changed it, crossing fingers :)
in case it doesn't like me, it's : P(n) equals product for x=0 to n of (sqrt(x)+i)
 
Well, by now I still haven't solved this problem but I found it's called the Spiral of Theodorus and there is no simple closed form solution althought the problem looks so simple :).
In addition, the solutions are converging series that, well... converge very very slowly.
So, I'm going to use a table of sampled values for my function and that's going to be all.
 
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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