The given function is .
Differentiating both sides with respect to x, we get
For f(x) to be decreasing,
∴ x ∈ (0, ∞)
Thus, the largest open interval in which the given function f(x) decreases is (0, ∞).
The largest open interval in which the function f(x) = decreases is ____(0, ∞)____.