《python语言程序设计》第3章编程题答案（下半）

wg19830119

3.15:

from turtle import*

penup()

goto(0,-100)

pendown()

circle(100)

penup()

goto(0,30)

left(180)

pendown()

circle(30,steps=3)

penup()

goto(-40,50)

pendown()

dot(20,'black')

penup()

goto(40,50)

pendown()

dot(20,'black')

penup()

goto(0,-50)

pendown()

right(30)

forward(60)

penup()

goto(0,-50)

pendown()

right(120)

forward(60)

hideturtle()

done()

3.16:

from turtle import*

penup()

goto(-200,0)

right(180)

pendown()

circle(60,steps=3)

penup()

goto(-100,-90)

right(225)

pendown()

circle(60,steps=4)

penup()

goto(20,-90)

left(8)

#right(180)

pendown()

circle(60,steps=5)

penup()

goto(160,-90)

setheading(0)

right(30)

pendown()

circle(60,steps=6)

penup()

goto(300,-90)

pendown()

left(8)

circle(60,steps=8)

done()

3.17:

from turtle import*

import math

x1,y1,x2,y2,x3,y3=eval(input('输入三个点的坐标：'))

side1=pow((x1-x2)**2+(y1-y2)**2,0.5)

side2=pow((x1-x3)**2+(y1-y3)**2,0.5)

side3=pow((x2-x3)**2+(y2-y3)**2,0.5)

s=(side1+side2+side3)/2

area=pow((s*(s-side1)*(s-side2)*(s-side3)),0.5)

#print(s,side1,side2,side3,area)

penup()

goto(x1,y1)

pendown()

write('p1('+str(x1)+','+str(y1)+')')

goto(x2,y2)

write('p2('+str(x2)+','+str(y2)+')')

goto(x3,y3)

write('p3('+str(x3)+','+str(y3)+')')

goto(x1,y1)

penup()

goto(0,-90)

pendown()

write('the area of triangle is  '+format(area,'.2f'))

done()

3.18:

from turtle import*

import math

x1,y1,x2,y2,x3,y3=eval(input('输入三个点的坐标：'))

a=pow((x1-x2)**2+(y1-y2)**2,0.5)

b=pow((x1-x3)**2+(y1-y3)**2,0.5)

c=pow((x2-x3)**2+(y2-y3)**2,0.5)

A=math.degrees(math.acos((a*a-b*b-c*c)/(-2*b*c)))

B=math.degrees(math.acos((b*b-a*a-c*c)/(-2*a*c)))

C=math.degrees(math.acos((c*c-b*b-a*a)/(-2*a*b)))

penup()

goto(x1,y1)

pendown()

write('A角：'+str(round(A*100)/100.0))

goto(x2,y2)

write('B角：'+str(round(B*100)/100.0))

goto(x3,y3)

write('C角：'+str(round(C*100)/100.0))

goto(x1,y1)

done()

3.19:

from turtle import*

import math

x1,y1,x2,y2=eval(input('输入两个点的坐标：'))

penup()

goto(x1,y1)

pendown()

write('p1('+str(x1)+','+str(y1)+')')

goto(x2,y2)

write('p2('+str(x2)+','+str(y2)+')')

hideturtle()

done()

huiming

回个帖子，下班咯~

xlg

介是神马？！！