Why do mathematicians use single-letter variables? I have much more experience programming than I do with advanced mathematics, so perhaps this is just a comfort thing with me, but I often get frustrated when I try to follow mathematical notation. Specifically, I get frustrated trying to keep track of what each variable signifies.
As a programmer, this would be completely unacceptable no matter how many comments you added explaining it:
float A(float P, float r, float n, float t) {
  return P * pow(1 + r / n, n * t);
}

Yet a mathematician would have no problem with this:

$A = P\ \left(1+\dfrac{r}{n}\right)^{nt}$
where
$A$ = final amount
$P$ = principal amount (initial investment)
$r$ = annual nominal interest rate (as a decimal)
$n$ = number of times the interest is compounded per year
$t$ = number of years

So why don't I ever see the following?
$\text{final_amount} = \text{principal}\; \left(1+\dfrac{\text{interest_rate}}{\text{periods_per_yr}}\right)^{\text{periods_per_yr}\cdot\text{years}}$

I write: Solutions of quadratic equation $ax^2 + bx + c=0$ are $(-b\pm\sqrt{b^2-4ac})/(2a)$.  I would not want to write this with time in place of $x$ and acceleration_of_gravity in place of $a$ and so on!
