1. **State the problem:** We are given the function $f(x) = 2x^3$ and asked which statement about the behavior of $f$ at the point $(0,0)$ is true.
2. **Recall the definitions:**
- A **corner** occurs where the function is continuous but the derivative from the left and right do not match.
- A function **does not have a derivative** at a point if the derivative is undefined there.
- A **horizontal tangent line** means the derivative at that point is zero.
- A **vertical tangent line** means the derivative tends to infinity or is undefined due to vertical slope.
3. **Find the derivative:**
$$f'(x) = \frac{d}{dx}(2x^3) = 6x^2$$
4. **Evaluate the derivative at $x=0$:**
$$f'(0) = 6 \times 0^2 = 0$$
5. **Interpret the result:**
- Since $f'(0)$ exists and equals 0, the function is differentiable at 0.
- The derivative is continuous and smooth, so no corner exists at $(0,0)$.
- The tangent line at $(0,0)$ is horizontal because the slope is 0.
- The tangent line is not vertical because the derivative is finite.
**Final answer:** $f$ has a horizontal tangent line at $(0,0)$.
Horizontal Tangent Fdfd0B
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