import sympy as sym
import numpy as np
from IPython.display import display, Math
from sympy.abc import w,x,y,z,a,b,c,d
sym.init_printing()
vec = range(10,21)
vec
type(vec)
vec =list( range(10,21))
vec
# slicing
vec[2:5]
vec[2:9:2]
vec[::2]
vec[0:-1:2]
vec[::-1]