Saturday, August 1, 2026

2026/066) Determine all triples (a,b,c) of positive integers with $a^{b^c} = (a^b)^c$

 We are given $a^{b^c} = a^{bc}$


Or $a^{b^c-bc} = 1$
 

This has got 2 sets of solutions
 

1) a = 1 and b and c can be any positive integer
 

2) a = any positive integer other than 1 and
 

$b^c - bc = 0$
 

Or $b(b^{c-1}) = c$
 

As b is not zero so we have $ b^{c-1} = c $
 

if c = 1 we get b any number
 

Or $b= \sqrt[c-1]c$ $c>=2$
 

The root can be taken to be integer if c-1 = 1 or c =2 giving b = 2
 

So solution set $(1,b,c)$ or $(a,2,2)$ or $(a,b,1)$ where a,b,c are any integers