在曲线某一点做切线

x = np.arange(0,10,0.1)

def line1(x):
   return np.sin(x)*2

def slope(x):
   h = 1e-4
   k = (line1(x+h)-line1(x-h))/(2*h)
   b = line1(x)-k*x
   return k,b 
# 通过计算导数的方法得到x点的斜率k，再计算在x点的截距b

y = line1(x)
plt.plot(x,y)

k,b = slope(4)
x_slope = k*x +b 

plt.plot(x,x_slope)
plt.ylim(-3,3)
plt.show()