I dont know why cannot find widget or abbreviation for argument:'i1'. How to modify?

Question

from ipywidgets import interact
from pylab import *
from math import *
import matplotlib.pyplot as plt
import numpy as py

n1=0
n2=0

def Snell_law(n1,n2,i1):
%matplotlib.inline
axis[(-10,10,-10,10)]
grid()
axhline(color='c',linewidth=3)
t=np.arange(0,10,0.1)

if 90>=i1>asin(n2/n1)/pi*180:
x=sin(i1/180*pi)*t
y=cos(i1/180*pi)*t

x1=sin(i1/180*pi)*-t
y1=cos(i1/180*pi)*t

elif 0<i1<=asin(n2/n1)/pi*180:
x=sin(i1/180*pi)*t
y=cos(i1/180*pi)*t

x1=sin(i1/180*pi)*-t
y1=sin(i1/180*pi)*t

i2=asin(n1/n2*sin(x1))/pi*180
x2=sin(abs(n2)/180*pi)*-t
y2=cos(abs(n2)/180*pi)*-t

plt.plot(x,y,'-',label="rayon incident")
plt.plot(x1,y1,'--',label="rayon refracte")
plt.plot(x2,y2,'---',label="rayon reflechi")
plt.legend()
plt.title("Animation Snell_law")
plt.show()

interact(Snell_law, i1=(0,90,1) ,n1=(1,3,0.1) ,n2=(1,3,0.1))

Answer 1

Before the if statement, try setting x, y, x1, y1, x2, and y2 to 0.

Answer 2

I don't think this is the answer to your question, but you forgot to add a colon at the end of the line on your first if statement on line 14.