01-基石题-test
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01-基石题-test/模型qwen3-coder-plus工具iflow/figure.png
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01-基石题-test/模型qwen3-coder-plus工具iflow/figure.png
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01-基石题-test/模型qwen3-coder-plus工具iflow/plot.py
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01-基石题-test/模型qwen3-coder-plus工具iflow/plot.py
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# /// script
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# requires-python = ">=3.11"
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# dependencies = ["numpy", "matplotlib"]
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# ///
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import numpy as np
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import matplotlib.pyplot as plt
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# 设置字体(优先使用中文字体,DejaVu Sans 作为 fallback)
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plt.rcParams['font.sans-serif'] = ['WenQuanYi Micro Hei', 'Noto Sans CJK SC', 'Microsoft YaHei', 'SimHei', 'SimSun', 'DejaVu Sans']
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plt.rcParams['axes.unicode_minus'] = False
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# 绑定图像尺寸和 DPI
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plt.figure(figsize=(8, 6), dpi=150)
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# 定义二次函数 y = -2x^2 + 8x - 3
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def quadratic_func(x):
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return -2*x**2 + 8*x - 3
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# 生成x值,覆盖关键区域
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x = np.linspace(-1, 5, 400)
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y = quadratic_func(x)
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# 绘制函数曲线
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plt.plot(x, y, label=r'$y = -2x^2 + 8x - 3$', color='blue', linewidth=2)
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# 标出顶点 (2, 5)
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vertex_x, vertex_y = 2, 5
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plt.plot(vertex_x, vertex_y, 'ro', markersize=8, label=f'顶点 ({vertex_x}, {vertex_y})')
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# 添加网格
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plt.grid(True, linestyle='--', alpha=0.6)
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# 设置坐标轴标签和标题
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plt.xlabel('x', fontsize=12)
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plt.ylabel('y', fontsize=12)
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plt.title('二次函数 $y = -2x^2 + 8x - 3$ 的图像', fontsize=14)
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# 设置坐标轴范围
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plt.xlim(-1, 5)
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plt.ylim(-5, 7)
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# 添加图例
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plt.legend()
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# 在顶点处添加注释
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plt.annotate(f'顶点\n({vertex_x}, {vertex_y})',
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xy=(vertex_x, vertex_y),
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xytext=(vertex_x + 1.2, vertex_y - 1),
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arrowprops=dict(arrowstyle='->', color='red', lw=1.5),
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fontsize=12,
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color='red',
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ha='center')
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# 保存图像
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plt.savefig('figure.png', bbox_inches='tight')
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plt.close()
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print("图像已保存: figure.png")
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01-基石题-test/模型qwen3-coder-plus工具iflow/report.md
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01-基石题-test/模型qwen3-coder-plus工具iflow/report.md
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# 二次函数 $y = -2x^2 + 8x - 3$ 求解报告
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## 1. 🎯 问题描述
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已知二次函数 $y = -2x^2 + 8x - 3$,求:
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1. 函数的顶点坐标
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2. 函数的最大值
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需要绘图。
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## 2. ✅ 最终结论
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对于二次函数 $y = -2x^2 + 8x - 3$:
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1. 顶点坐标为 (2, 5)
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2. 由于函数开口向下($a = -2 < 0$),顶点是函数的最大值点,因此函数的最大值为 5
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## 3. 📈 可视化
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**图表说明**:
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- 蓝色曲线:函数 $y = -2x^2 + 8x - 3$
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- 红色圆点:顶点 (2, 5)
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- 从图中可以清楚地看到函数开口向下,顶点为最高点
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## 4. 🧠 数学建模与解题过程
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<details>
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<summary><strong>点击展开</strong></summary>
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**问题分析**:这是一个标准的二次函数求顶点和最值问题。给定函数 $y = -2x^2 + 8x - 3$ 是一个开口向下的抛物线(因为二次项系数 $a = -2 < 0$),所以存在最大值。
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**方法选择**:可以使用导数方法或顶点公式方法求解。
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**推导过程**:
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1. **使用导数方法**:
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- 对函数 $y = -2x^2 + 8x - 3$ 求导:$y' = -4x + 8$
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- 令导数为0:$-4x + 8 = 0$
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- 解得 $x = 2$
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2. **求顶点的y坐标**:
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- 将 $x = 2$ 代入原函数:$y = -2(2)^2 + 8(2) - 3 = -8 + 16 - 3 = 5$
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- 所以顶点坐标为 (2, 5)
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3. **验证函数开口方向**:
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- 二次项系数 $a = -2 < 0$,所以函数开口向下
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- 因此顶点是函数的最大值点
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4. **使用顶点公式验证**:
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- 对于二次函数 $y = ax^2 + bx + c$,顶点坐标为 $(-\frac{b}{2a}, f(-\frac{b}{2a}))$
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- 其中 $a = -2$, $b = 8$, $c = -3$
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- $x = -\frac{8}{2 \times (-2)} = -\frac{8}{-4} = 2$
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- $y = -2(2)^2 + 8(2) - 3 = 5$
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- 验证结果一致
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</details>
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## 5. 📊 运行结果
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<details>
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<summary><strong>点击展开</strong></summary>
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```
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给定二次函数: y = -2*x**2 + 8*x - 3
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函数的一阶导数: 8 - 4*x
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导数为0的点: [2]
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顶点坐标: (2, 5)
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函数的二阶导数: -4
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由于二次项系数为负数,函数开口向下,顶点为最大值点
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函数的最大值: 5
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使用顶点公式验证:
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顶点x坐标: x = -b/(2a) = -8/(2*-2) = 2.0
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顶点y坐标: y = -2*(2.0)^2 + 8*(2.0) + -3 = 5.0
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========================================
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最终答案:
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1. 函数的顶点坐标: (2, 5)
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2. 函数的最大值: 5
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========================================
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```
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</details>
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01-基石题-test/模型qwen3-coder-plus工具iflow/solve.py
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01-基石题-test/模型qwen3-coder-plus工具iflow/solve.py
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# /// script
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# requires-python = ">=3.11"
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# dependencies = ["sympy", "numpy", "matplotlib"]
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# ///
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import sympy as sp
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import numpy as np
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# 定义变量
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x = sp.symbols('x', real=True)
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# 定义二次函数 y = -2x^2 + 8x - 3
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func = -2*x**2 + 8*x - 3
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print("给定二次函数: y =", func)
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# 方法1: 使用导数求顶点
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# 顶点的x坐标是导数为0的点
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derivative = sp.diff(func, x)
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print("函数的一阶导数:", derivative)
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# 求导数为0的点
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critical_points = sp.solve(derivative, x)
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print("导数为0的点:", critical_points)
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# 顶点的x坐标
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vertex_x = critical_points[0]
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vertex_y = func.subs(x, vertex_x)
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print(f"顶点坐标: ({vertex_x}, {vertex_y})")
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# 判断最大值还是最小值
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second_derivative = sp.diff(derivative, x)
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print("函数的二阶导数:", second_derivative)
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if second_derivative < 0:
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print("由于二次项系数为负数,函数开口向下,顶点为最大值点")
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print(f"函数的最大值: {vertex_y}")
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elif second_derivative > 0:
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print("由于二次项系数为正数,函数开口向上,顶点为最小值点")
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print(f"函数的最小值: {vertex_y}")
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else:
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print("这不是二次函数")
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# 方法2: 使用二次函数顶点公式验证
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# 对于二次函数 y = ax^2 + bx + c,顶点x坐标为 x = -b/(2a)
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a = -2
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b = 8
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c = -3
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vertex_x_formula = -b / (2*a)
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vertex_y_formula = a * vertex_x_formula**2 + b * vertex_x_formula + c
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print("\n使用顶点公式验证:")
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print(f"顶点x坐标: x = -b/(2a) = {-b}/(2*{a}) = {vertex_x_formula}")
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print(f"顶点y坐标: y = {a}*({vertex_x_formula})^2 + {b}*({vertex_x_formula}) + {c} = {vertex_y_formula}")
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# 最终结果
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print("\n" + "="*40)
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print("最终答案:")
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print(f"1. 函数的顶点坐标: ({vertex_x}, {vertex_y})")
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print(f"2. 函数的最大值: {vertex_y}")
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print("="*40)
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