Координатная плоскость, построение двух функций с пересечением

from tkinter import *
from math import *
root = Tk()
root.geometry ('1024x1080')
 
ntre = Entry(root,width=2)              
ntre.grid(column = 0, row = 1)
 
lbl = Label(root, text = 'x**2+')
lbl.grid(column = 1, row = 1)
 
ntre1 = Entry(root,width=2)
ntre1.grid(column = 2, row = 1)
 
ntre2 = Entry(root,width=2)
ntre2.grid(column = 0, row = 2)
 
ntre3 = Entry(root,width=2)
ntre3.grid(column = 1, row = 2)
 
lbl = Label(root, text = 'x**3-')
lbl.grid(column = 1, row = 2)
 
ntre4 = Entry(root,width=2)
ntre4.grid(column = 2, row = 2)
 
 
def clickznak():
    a = ntre.get()
    ntre.delete(0,END)
    for i in range(-4000,4100):
        x = i/100
        h = 20
        y1 = x**2
        y2 = x**3
        draw(x,y1,canvas,h,h,7,'green')
        draw(x,y2,canvas,h,h,7,'black')
 
def clrbut():
    canvas.delete(ALL)
    canvas.create_line(512,1024,512,0,width=2,arrow=LAST)
    canvas.create_line(0,540,1024,540,width=2,arrow=LAST)
 
 
btn = Button(root,text = 'Отправить', command = clickznak)
btn.grid(column = 0, row = 4)
 
btn1 = Button(root,text = 'Очистить', command = clrbut)
btn1.grid(column = 0, row = 5)
 
canvas = Canvas(root,width = 1024, height = 1080,bg = 'white')
canvas.grid(column = 4, row = 6)
 
canvas.create_line(512,1024,512,0,width=2,arrow=LAST)
canvas.create_line(0,540,1024,540,width=2,arrow=LAST)
 
 
def draw(x,y,canvas,hx,hy,fat,color):
    x = x*hx
    y = y*hy
    x = x + int(canvas['width'])//2
    y = y + int(canvas['height'])//2
    y = int(canvas['height'])- y
    x = round(x)
    y = round(y)
    canvas.create_oval(x-fat//2,y-fat//2,x+fat//2,y+fat//2, fill = color)
    return (x,y)
root.mainloop()