What does ( 0.25)^(3n) converge towards? (EASY Q)

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Really quick question here:

I want to find the sommation of f(x) = 0.253n for x being a Natural ( N) number going from 0 to infinity.

k1k2n converges towards what, as a general rule?

Where k1, k2 are constants and n= 0,1,2,3 ...

EDIT: NO, not what it converges to, but what the sommation is equal to... as in f(0)+f(1) +f(2) + ...
 
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It's a geometric series isn't it? It's ((1/4)^3)^n. What do you know about the sum of geometric series?
 
Well, I'm looking for = ∑rn-1 for n going from 1 to infinity... But isn't there a formula for where n starts at 0?

I also know that you can play around sith Sn= (1-rn) / (1-r) , but I don't remember/know where this leads to.
 
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I'll help you out. The sum for n=0 to infinity of r^n is 1/(1-r) for r<1. That's the n->infinity limit of your Sn.
 
All right, thanks a lot
 
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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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