I have a truly simple inequality, which I want to prove using Mathematica:
$$ a^x \geq 1 ,\quad \quad with \quad 1\leq a \quad and \quad 1\leq x \quad a,x \in R$$
This is obviously true. When I try to solve this in Mathematica using for example:
Assuming[1 <= a && x >= 1, FullSimplify[a^x >= 1]]
the only output I get, is a^x >= 1 and not the desired True. Is Mathematica really not able to solve this simple problem or am I missing something basic here?
Of course, my real inequality is much more complicated, but I broke it down until I identified working with exponents as the problem here.
Note that
FullSimplify[]accepts a second argument of constraints/assumptions, soFullSimplify[a^x >= 1, 1 <= a && x >= 1]would be a shorter way to write your snippet. That being said, one way that might work when the first one doesn't would be to use the functionReduce[]in tandem withFullSimplify[]; thus,FullSimplify[Reduce[a^x >= 1 && a >= 1 && x >= 1, {a, x}], a >= 1 && x >= 1]is one possible solution.