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A math problem 120
1

(a+ 1/a)^2 = a^2+2a 1/a+ 1/a^2 = 4

a^2 + 1/a^2 = 4-2 = 2

A 4+ 1/A 4 = {A 2 as U, applying the previous results} = 2.

2

(a+ 1/a)^2 = a^2+2a 1/a+ 1/a^2 = n^2

a^2 + 1/a^2 =n^2 -2

A 4+ 1/A 4 = {A 2 as U, applying the previous results} = {(n 2-2) 2-2}) 2-2}

three

The selection (1) holds. When a= 1, (...) =2, and there are n (... * * * = 2 n in total.