Explanation

Given f(x) = x³ - (1/x³):

f(1/x) = (1/x)³ - (1/(1/x)³) = (1/x³) - x³

Now, let's calculate f(x) + f(1/x):

f(x) + f(1/x) = (x³ - 1/x³) + (1/x³ - x³)

= x³ - x³ - 1/x³ + 1/x³

= 0