Like many who use brilliant, I faked my age. For those who know me, this is a give away. Seriously, a give away:
What is the minimum value of A if A is a positive (obviously) integer?
g = 2 . 2 1 8 6 5 4 7 6 2 lo g g g lo g g g lo g g g A
This question was inspired by the boredom of Geography, therefore the log constant is g.
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This solution is for people who have not learned much about calculus yet (like me). If you have better solutions, post it up:
let
g = 2 . 2 1 8 6 5 4 7 6 2 lo g g g lo g g g lo g g g A = n ,
then,
g g g n g g g = A
its a bit hard to see so here it is: (g^((g^((g^n) g)) g))*g=A
Graphing:
y = g g g x g g g
it shows that the minimum for y is when x is as negative as possible, therefore, the minimum of A is extremely close to:
g g g − 9 ∗ 1 0 9 9 g g g
which can be easily calculated with a scientific calculator. This gives
A ≈ 1 2 . 9 9 9 9 9 9 9 9
And since A is an integer, A = 1 3
Hey Julian Poon! I could understand upto the step before graphing. I cannot understand from there. Could you enlighten me from there, Please!
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It is just the way logarithms work. You can easily derive it by some logic. It pretty much just shows that the smallest value for y would be reached as x approaches -infinity
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For any logarithmic function, f ( x ) = lo g c x , c = 1 , the greatest lower bound for the domain is 0.
Which means: g lo g g g lo g g g A > 0 .
After isolating A , we get: A > g g + 1 ≈ 1 2 . 9 9 9 9 9 9 9 9
∴ A = 1 3