[Sqrt(2)]^[Sqrt(2)]^[Sqrt(2)]^[Sqrt(2)] ........... infinite = x
[Sqrt(2)]^x = x
Sqrt(2) = x^(1/x)
Now 2 and 4 satisfies this equation but for any value of n
[Sqrt(2)]^[Sqrt(2)]^[Sqrt(2)]^[Sqrt(2)] .......... n terms < 2
So only 2 will be the solution