Tagged Questions
4
votes
1answer
113 views
Operators - sums, products, exponents, etc.
$(x + x + \cdots + x)$, where $x$ added $n$ times can be written as $x * n$.
$(x * x * \cdots * x)$, where $x$ multiplied $n$ times can be written as $x ^ n$.
Is there an operator, such that if ...
0
votes
2answers
46 views
Computing $\left\lfloor\sum_{k = 1}^{n}{\varphi^{3k}}\right\rfloor$
I'm trying to find $\left\lfloor\sum_{k = 1}^{n}{\varphi^{3k}}\right\rfloor$ mod $m$. $\varphi = \frac{1 + \sqrt{5}}{2}$ and $\varphi^3 = 2 + \sqrt{5}$.
But honestly I'm not even sure where to start. ...
3
votes
5answers
133 views
Summation over exponent $\sum_{i=0}^k 4^i= \frac{4^{k+1}-1}3$
Why does $\sum_{i=0}^k 4^i= \frac{4^{k+1}-1}3$, where does that 3 comes from?
Ok, from your answers I looked it up on wikipedia Geometric Progression, but to derive the formula it says to multiply by ...
