There is only one solution: x = 2020/-305 = -404/61
f(x)=x[x[x[x]]]
I had trouble solving this purely analytically.
It's easy to rule out positive solutions because f(7)=2401 and if x is just under 7, it drops to just under 2002. f(7-e)=2002-286e for very small e.
Consider negative solutions. With a table you can hone in on x very close to -6.623
letting x=-6.623 and evaluating by hand
[x]=-7
x[x]=46.361
x[x[x]]=-304.658
f(x)=2020.015
which is pretty close. If we assume [x[x[x]]]=-305 we can try x=2020/-305 and it works.
|
|
Posted by Jer
on 2020-09-15 12:47:42 |
Solution
