Which is bigger, $2^{25}$ or $25^{2}$ ?

Q: Which is bigger, 2^25 or 25^2?

2^25 is bigger: 2^25 = 33554432 and 25^2 = 625.

$2^{25}$ is bigger: $2^{25}$ = 33554432 and $25^{2}$ = 625.

2^{25} = 33554432\ >\ 25^{2} = 625

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The curve ln x / x, which decides every comparison of a^b with b^a. 2^25 against 25^2 is the same question as which of the two marked points is higher; the curve peaks at x = e.

How to work it out

1
Compute both exactly: $2^{25}$ = 33554432 and $25^{2}$ = 625.
2
So $2^{25}$ is bigger.
3
The reason: taking logs, $a^{b}$ against $b^{a}$ is the same as $\frac{\ln a}{a}$ against $\frac{\ln b}{b}$ . The function $\frac{\ln x}{x}$ rises until $x = e \approx 2.718$ and falls afterwards. For 2 and 25 it depends: $2^{4}$ = $4^{2}$ are equal, $2^{3}$ < $3^{2}$ , and $2^{b}$ > $b^{2}$ for every b ≥ 5.
$\frac{\ln 2}{2}\ >\ \frac{\ln 25}{25}$

LaTeX source of the formulas on this page

\[ 2^{25} = 33554432\ >\ 25^{2} = 625 \]
\[ \frac{\ln 2}{2}\ >\ \frac{\ln 25}{25} \]

Questions

Which is bigger,

2^{25}

25^{2}

$2^{25}$ is bigger: $2^{25}$ = 33554432 and $25^{2}$ = 625.

Which is bigger, 2252^{25}225 or 25225^{2}252?

How to work it out

Questions

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Which is bigger, $2^{25}$ or $25^{2}$ ?