python海龟库画同心椭圆

根据提供的引用内容，turtle库画同心圆的原理是通过不断改变小海龟的位置和半径来实现的。同样的，画同心椭圆也可以通过类似的方法来实现。具体步骤如下：

1. 导入turtle库

import turtle

2. 创建画布和画笔

canvas = turtle.Screen() # 创建画布
pen = turtle.Turtle() # 创建画笔

3. 设置画笔的属性

pen.color('red') # 设置画笔颜色
pen.pensize(2) # 设置画笔宽度

4. 定义画同心椭圆的函数

def draw_ellipse(pen, a, b, x, y):
    pen.penup()
    pen.goto(x, y)
    pen.pendown()
    for i in range(0, 360, 5):
        radian = i * 3.14 / 180
        x = a * math.cos(radian)
        y = b * math.sin(radian)
        pen.goto(x, y)

5. 调用画同心椭圆的函数

import math

a = 100 # 长半轴
b = 50 # 短半轴
x = 0 # 椭圆中心x坐标
y = 0 # 椭圆中心y坐标

for i in range(1, 6):
    draw_ellipse(pen, a * i, b * i, x, y)

6. 隐藏小海龟

pen.hideturtle()

完整代码如下：

import turtle
import math

canvas = turtle.Screen()
pen = turtle.Turtle()

pen.color('red')
pen.pensize(2)

def draw_ellipse(pen, a, b, x, y):
    pen.penup()
    pen.goto(x, y)
    pen.pendown()
    for i in range(0, 360, 5):
        radian = i * 3.14 / 180
        x = a * math.cos(radian)
        y = b * math.sin(radian)
        pen.goto(x, y)

a = 100
b = 50
x = 0
y = 0

for i in range(1, 6):
    draw_ellipse(pen, a * i, b * i, x, y)

pen.hideturtle()