I tried to draw a graph of sin, but I got an error. What's wrong?

%matplotlib inline
import matplotlib.pyplot asplt

import numpy as np
X=np.linspace(0,2*np.pi)
y = np.sin(X)

plt.plot(x,y)

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NameError Traceback (most recent call last)
~\AppData\Local\Temp\ipykernel_26536\2280643985.py in<module>
      3 y = np.sin(X)
      4 
---->5plt.plot(x,y)

NameError: name 'x' is not defined