It is proved that if f (x) is differentiable on the interval I and the derivative function on I is bounded, then f (x) is uniformly continuous on I

It is proved that if f (x) is differentiable on the interval I and the derivative function on I is bounded, then f (x) is uniformly continuous on I

Let f '(x) | ≤ M
Then, for any x, y ∈ I, according to Lagrange's mean value theorem, f (y) - f (x) ≤ m y-x
Therefore, for any given ε > 0, take δ = ε / m, then when Y-X ﹤ δ, ﹤ f (y) - f (x) ﹤ m ﹤ Y-X ﹤ m (ε / M) = ε
The proposition is proved, and the proof is finished