Derivative Curve 74Dbe9
1. **Problem Statement:** We are given the graph of the first derivative $f'(x)$ of a continuous function $f$ on $\mathbb{R}$. We need to identify which statement among (a), (b), (c), and (d) is incorrect.
2. **Recall Key Concepts:**
- A **critical point** of $f$ occurs where $f'(x) = 0$ or $f'(x)$ is undefined.
- An **inflection point** occurs where the concavity of $f$ changes, i.e., where $f''(x)$ changes sign.
- The function $f$ is **convex up** (concave up) on intervals where $f''(x) > 0$.
3. **Analyze the Graph of $f'(x)$:**
- The graph of $f'(x)$ is positive and steeply increasing near $x=0$.
- There is a vertical asymptote near $x=0$ for $f'(x)$, indicating $f'(x)$ is not defined at $x=0$.
- $f'(x)$ is positive on both sides of $0$ but not zero at $0$.
4. **Evaluate Each Statement:**
(a) **Inflection point at $x=0$:**
- Since $f'(x)$ is increasing steeply and has a vertical asymptote at $0$, $f''(x)$ changes sign around $0$.
- This implies an inflection point at $x=0$.
- So, (a) is **true**.
(b) **$f$ is convex up on $(-\infty,0)$:**
- Convex up means $f''(x) > 0$.
- Since $f'(x)$ is increasing on $(-\infty,0)$, $f''(x) > 0$ there.
- So, (b) is **true**.
(c) **$f$ has a critical point at $x=0$:**
- Critical points require $f'(0) = 0$ or $f'(0)$ undefined.
- Here, $f'(x)$ has a vertical asymptote at $0$, so $f'(0)$ is undefined.
- Thus, $x=0$ is a critical point.
- So, (c) is **true**.
(d) **$f$ is convex up on $(0, \infty)$:**
- $f'(x)$ is positive but flattening out on $(0, \infty)$, meaning $f'(x)$ is decreasing or constant.
- If $f'(x)$ is decreasing, then $f''(x) < 0$ on $(0, \infty)$.
- So, $f$ is **not** convex up on $(0, \infty)$.
- Therefore, (d) is **false**.
5. **Final Answer:** The wrong statement is (d).
$$\boxed{\text{The wrong statement is (d).}}$$