函数图像

复制import numpy as np
import matplotlib.pyplot as plt

# 定义函数和 x 范围
def f(x):
    return np.sin(x) + 0.5 * np.cos(2 * x)

x = np.linspace(-10, 10, 1000)
y = f(x)

# 绘图并设置缩放
plt.figure(figsize=(8, 4))
plt.plot(x, y, label='y = sin(x) + 0.5*cos(2x)')
plt.xlim(-5, 5)  # 水平缩放
plt.ylim(-2, 2)  # 垂直缩放
plt.grid(True, alpha=0.3)
plt.legend()
plt.show()

复制package main

import (
	"fmt"
	"math"
	"os"
	"strconv"
)

// 计算 y = sin(x) + 0.5*cos(2x) 在 x 处的值
func f(x float64) float64 {
	return math.Sin(x) + 0.5*math.Cos(2*x)
}

func main() {
	if len(os.Args) < 2 {
		fmt.Println("用法: go run main.go <x值>")
		return
	}
	x, err := strconv.ParseFloat(os.Args[1], 64)
	if err != nil {
		fmt.Println("无效的 x 值:", err)
		return
	}
	y := f(x)
	fmt.Printf("f(%.4f) = %.6f\n", x, y)
}

复制// 使用 Canvas API 绘制函数图像
const canvas = document.getElementById('plot');
const ctx = canvas.getContext('2d');

// 定义函数
const f = (x) => Math.sin(x) + 0.5 * Math.cos(2 * x);

// 绘图参数
const xMin = -5, xMax = 5;
const yMin = -2, yMax = 2;
const width = canvas.width, height = canvas.height;

// 坐标映射：世界坐标 → 像素坐标
const toPixelX = (x) => ((x - xMin) / (xMax - xMin)) * width;
const toPixelY = (y) => height - ((y - yMin) / (yMax - yMin)) * height;

// 绘制曲线
ctx.beginPath();
ctx.strokeStyle = 'blue';
ctx.lineWidth = 2;

const step = (xMax - xMin) / width;
for (let px = 0; px <= width; px++) {
    const x = xMin + (px / width) * (xMax - xMin);
    const y = f(x);
    const py = toPixelY(y);
    px === 0 ? ctx.moveTo(px, py) : ctx.lineTo(px, py);
}
ctx.stroke();