#範例10-6：以泰勒多項式逼近sin(x)函數
from sympy import *
x = symbols('x')
f = Function('f')(x)
f = sin(x)

ty1 = series(f, x, x0=0, n=24).removeO()
ty2 = series(f, x, x0=0, n=25).removeO()
ty3 = series(f, x, x0=0, n=26).removeO()
#畫圖
p1 = plot(f, ty1, ty2, ty3, (x, -10, 10), show='False')
p1[0].line_color= 'red'
p1[1].line_color= 'blue'
p1[2].line_color= 'green'
p1[3].line_color= 'yellow'
p1[0].label= '$sin(x)$'
p1[1].label= '$taylor(n=23)$'
p1[2].label= '$taylor(n=24)$'
p1[3].label= '$taylor(n=25)$'
p1.legend = True
p1.show()