一阶导数计算

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x=np.arange(1,100) y = np.sin(0.1*x)   def D_1(x,y):     n = len(x)     d = np.zeros(n)     d[0] = (y[1]-y[0])/(x[1]-x[0])     d[n-1] = (y[n-1]-y[n-2])/(x[n-1]-x[n-2])     for i in range(1,n-1):         d[i] = (((y[i+1]-y[i])/(x[i+1]-x[i])+(y[i]-y[i-1])/(x[i]-x[i-1])))/2     return d     d = 10*D_1(x,y) y1 = np.cos(0.1*x)     fig,ax=plt.subplots() ax.plot(x,y,'b-',label='sin(x)') ax.plot(x,d,'r-',label='derivative') ax.plot(x,y1,'g-.',label='cos(x)') ax.legend(loc=1) plt.show()