1. **State the problem:** Sketch the graph of the polynomial function $$y = 3x^4 + 4x^3 + 1$$ and analyze its critical points.
2. **Find the value at $$x=0$$:**
$$y(0) = 3(0)^4 + 4(0)^3 + 1 = 1$$
So the graph passes through the point $$(0,1)$$.
3. **Find the first derivative to locate critical points:**
$$y' = \frac{d}{dx}(3x^4 + 4x^3 + 1) = 12x^3 + 12x^2$$
4. **Factor the derivative:**
$$y' = 12x^2(x + 1) = 0$$
Critical points occur where $$y' = 0$$, so:
$$12x^2 = 0 \implies x=0$$
$$x + 1 = 0 \implies x = -1$$
5. **Second derivative to determine concavity:**
$$y'' = \frac{d}{dx}(12x^3 + 12x^2) = 36x^2 + 24x$$
6. **Evaluate $$y''$$ at critical points:**
- At $$x=0$$:
$$y''(0) = 36(0)^2 + 24(0) = 0$$ (inconclusive, test further or use first derivative test)
- At $$x=-1$$:
$$y''(-1) = 36(-1)^2 + 24(-1) = 36 - 24 = 12 > 0$$, so $$x=-1$$ is a local minimum.
7. **Summary:**
- The graph passes through $$(0,1)$$.
- Critical points at $$x=0$$ and $$x=-1$$.
- Local minimum at $$x=-1$$.
- The function is a quartic polynomial with positive leading coefficient, so it tends to $$+\infty$$ as $$x \to \pm \infty$$.
This analysis helps sketch the curve showing the shape and critical points.
Polynomial Graph 4C34Bf
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