嘿试图学习如何编码,我不能想出这个练习。 具体获取精确的y轴截距点。 给出的公式适用于获取x轴点,但我无法弄清楚如何获得y轴点。
练习:
输入:圆的半径和线的y - 截距。
输出:使用给定的y截距在窗口上用水平线绘制的圆。标记交叉点的两个点。 打印交点的x值*公式:x =±√r^ 2 - y ^ 2
Code::
from graphics import *
from math import *
def main():
# enter radius and the y intercept of the line
radius = eval(input("Put in radius:: "))
yinter = eval(input("Put in y intersec:: "))
#Draw window + circle + line
win = GraphWin()
win.setCoords(-10.0, -10.0, 10.0, 10.0)
circle = Circle(Point(0.0,0.0), radius)
mcircle = Circle(Point(0.0,0.0), 0.5)
circle.draw(win)
mcircle.draw(win)
line = Line(Point(-10, 0), Point(10, yinter))
line.draw(win)
#Calculate x axis points of intersept
xroot1 = sqrt(radius * radius - yinter * yinter)
xroot2 = -abs(xroot1)
print("Xroot 1 : ", xroot1)
print("Xroot 2 : ", xroot2)
x = 0
yroot1 = sqrt(radius * radius - x * x)
yroot2 = -abs(yroot1)
print("Yroot 1 : ", yroot1)
print("Yroot 2 : ", yroot2)
#mark two points of intersept in red
sc1 = Circle(Point(xroot1, yroot1), 0.3)
sc1.setFill('red')
sc2 = Circle(Point(xroot2, yroot2), 0.3)
sc2.setFill('red')
sc1.draw(win)
sc2.draw(win)
main()
Answer - With Radius of 8 and Y intersect point of 2
Yroot1 = 7.75
Yroot2 = -7.75
Xroot1 = 8.0
Xroot2 = -8.0
答案 0 :(得分:0)
对于y坐标,您可以使用类似的公式:
y =±sqrt(r ^ 2 - x ^ 2)
并且标记根部的所有事情都是一样的。
答案 1 :(得分:0)
您应该编写如下代码:
x = sqrt(r ** 2 - y ** 2)
line = Line(Point(-10, 0), Point(10, yinter))
line.draw(win)
Line(Point(-10,0) is wrong, it should read:
Line(Point(-10,yinter).
同时设置Xroot1
和Xroot2 = 0
或-x=0, x=0
答案 2 :(得分:0)
我刚刚想出了一个子程序来寻找交叉点,同时解决另一个与Zelle图形相关的SO问题。可能有一些方法可以简化数学运算,但我还有很长的路要走:
from graphics import *
def intersection(center, radius, p1, p2):
""" find the two points where a secant intersects a circle """
dx, dy = p2.x - p1.x, p2.y - p1.y
a = dx**2 + dy**2
b = 2 * (dx * (p1.x - center.x) + dy * (p1.y - center.y))
c = (p1.x - center.x)**2 + (p1.y - center.y)**2 - radius**2
discriminant = b**2 - 4 * a * c
assert (discriminant > 0), 'Not a secant!'
t1 = (-b + discriminant**0.5) / (2 * a)
t2 = (-b - discriminant**0.5) / (2 * a)
return Point(dx * t1 + p1.x, dy * t1 + p1.y), Point(dx * t2 + p1.x, dy * t2 + p1.y)
def main(win):
center = Point(0.0, 0.0)
# Enter radius
radius = float(input("Put in radius: "))
# Draw circle and center dot
Circle(center, radius).draw(win)
Circle(center, 0.3).draw(win)
# Enter the y intercept of the line
yinter = float(input("Put in y intercept: "))
# Draw line
p1, p2 = Point(-10.0, 0.0), Point(10.0, yinter)
Line(p1, p2).draw(win)
# Mark two points of intercept in red
for i, root in enumerate(intersection(center, radius, p1, p2), start=1):
print("Root {}:".format(i), root)
dot = Circle(root, 0.3)
dot.setFill('red')
dot.draw(win)
win = GraphWin()
win.setCoords(-10.0, -10.0, 10.0, 10.0)
main(win)
win.getMouse()
<强>输出强>
注意强>
您可以获得不产生割线的值输入,例如半径为2,截距为8.您的代码没有考虑到这一点 - 如果发生断言,上面只会抛出一个断言错误。但您可以将其升级为可以捕获和修复的错误。