f(x)=a[(x+2)(x−1)(x−N)]
W(−1∣−2):
f(−1)=a[(−1+2)(−1−1)(−1−N)]=−2a[(−1−N)]=−2
a[(−1−N)]=1
a=−1−N1=−1+N1:
f(x)=−1+N1[(x+2)(x−1)(x−N)]
f′(x)=−1+N1[(x−1)(x−N)+(x+2)(x−N)+(x+2)(x−1)]
f′′(x)=−1+N1[(x−N)+(x−1)+(x−N)+(x+2)+(x−1)+(x+2)]
W(−1∣...):
f′′(−1)=−1+N1[(−1−N)+(−1−1)+(−1−N)+(−1+2)+(−1−1)+(−1+2)]
f′′(−1)=−1+N1[(−4−2N)]
−1+N1[(−4−2N)]=0
N=−2 a=1: :
f(x)=(x+2)(x−1)(x+2)=(x+2)2(x−1)
