Here is a nice old school question. "Legendary" question 6 from the junior maths tournament of 1988.
Let a and b be positive integers in the equation (a^2 + b^2)/(ab+1). Show that this equation is the square of an integer.
Pic related
If you cant do it dont fret not many can, but what are your ideas about these type of questions that take 2 variables and "push" them into a 3D sense?
>>8795875
a=3
b=4
(a^2 + b^2)/(ab+1) = 25/13
>Show that this equation is the square of an integer.
???
let
a=1
b=1
(a^2 + b^2)/(ab+1) = 2/2 = 1
1^2=1
>>8795895
Square of an integer almost means 2^n so sub in a = 0 and b = 2 and u get 4 which is 2^2 aswell
>>8795935
Keep going
>>8795875
Looks like Vieta jumping might work.
>>8795937
what???
(a^2+b^2)/(ab+1) is not always the square of an integer, so the question of the OP is retarded, and false.
>>8796023
Wikipedia Vieta jumping
>>8796024
no thanks, I'd rather derive it myself.
>>8795875
for the case b = a^3 we have
(a^2+b^2)/(ab+1) = (a^2+a^6)/(a^4+1) = a^2(1+a^4)/(1+a^4) = a^2
unfortunately this doesn't cover all cases
>>8796325
spoken like a true mathematician
>>8796325
kek