2. Recall that we proved f(z) = VE is continuous on its domain [0, 00). Explain why f(z) is uniformly contimuous on la, b) for any b> a20.

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### Understanding Continuity and Uniform Continuity

#### Problem 2:
Recall that we proved \( f(x) = \sqrt{x} \) is continuous on its domain \([0, \infty)\). Explain why \( f(x) \) is uniformly continuous on \([a, b]\) for any \( b > a \geq 0 \).

---

In this problem, we investigate the continuity properties of the square root function \( f(x) = \sqrt{x} \). We already know that it is continuous over the entire domain from zero to infinity. However, we need to explore why this function exhibits uniform continuity over any closed interval \([a, b]\), where \( b \) is greater than \( a \) and both are non-negative. 

**Definitions:**

1. **Continuity**: A function \( f \) is continuous at a point \( x = c \) if:
   \[
   \lim_{{x \to c}} f(x) = f(c)
   \]

2. **Uniform Continuity**: A function \( f \) is uniformly continuous on a set \( S \) if for every \( \epsilon > 0 \), there exists a \( \delta > 0 \) such that for all \( x, y \in S \), if \( |x - y| < \delta \), then \( |f(x) - f(y)| < \epsilon \).

**Explanation:**

The key difference between continuity and uniform continuity is how the choice of \( \delta \) is determined. In continuity, \( \delta \) can depend on the specific point in the domain, while in uniform continuity, a single \( \delta \) must work for any point within the entire specified interval.

For \( f(x) = \sqrt{x} \), on the interval \([a, b]\), the function does not have steep gradients or discontinuities, ensuring that small changes in \( x \) yield small changes in \( f(x) \). This consistent behavior across the interval is why the function is uniformly continuous.
Transcribed Image Text:### Understanding Continuity and Uniform Continuity #### Problem 2: Recall that we proved \( f(x) = \sqrt{x} \) is continuous on its domain \([0, \infty)\). Explain why \( f(x) \) is uniformly continuous on \([a, b]\) for any \( b > a \geq 0 \). --- In this problem, we investigate the continuity properties of the square root function \( f(x) = \sqrt{x} \). We already know that it is continuous over the entire domain from zero to infinity. However, we need to explore why this function exhibits uniform continuity over any closed interval \([a, b]\), where \( b \) is greater than \( a \) and both are non-negative. **Definitions:** 1. **Continuity**: A function \( f \) is continuous at a point \( x = c \) if: \[ \lim_{{x \to c}} f(x) = f(c) \] 2. **Uniform Continuity**: A function \( f \) is uniformly continuous on a set \( S \) if for every \( \epsilon > 0 \), there exists a \( \delta > 0 \) such that for all \( x, y \in S \), if \( |x - y| < \delta \), then \( |f(x) - f(y)| < \epsilon \). **Explanation:** The key difference between continuity and uniform continuity is how the choice of \( \delta \) is determined. In continuity, \( \delta \) can depend on the specific point in the domain, while in uniform continuity, a single \( \delta \) must work for any point within the entire specified interval. For \( f(x) = \sqrt{x} \), on the interval \([a, b]\), the function does not have steep gradients or discontinuities, ensuring that small changes in \( x \) yield small changes in \( f(x) \). This consistent behavior across the interval is why the function is uniformly continuous.
Expert Solution
Step 1

 
definition : for all ε>0 there exists a δ>0 ,such that for all x,yX, |x-y|<δ|f(x)-f(y)|<ε.

Given ε> 0 ,pick δ = ε2 .

First note that | x  y|  | x + y|.

Hence if |x  y| < δ = ε2, 

then we have |  x   y|2  | x   y|| x +  y| = |x  y| < ε2 ,

hence|f(x)-f(y)|= |  x  y| < ε when ever |x-y|<δ. This shows that f(x) =  x is uniformly continuous on [0, )

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