Find the stationary points.
f(x) = x + 16/x
f '(x) = 1 - 16/x ²
Solve f '(x) = 0.
1 - 16/x ² = 0 → x ² = 16 → (x - 4) (x + 4) = 0
→ x = -4, x = 4
Check the value of f at the stationary points. x = -4 is not in the provided domain so we can omit it.
f (4) = 8
Check the value of f at the boundary of the domain.
f (0.2) = 401/5 = 80.2
f (16) = 17
Then over [0.2, 16], we have max(f ) = 401/5 and min(f ) = 8.
