A=R C A
a0, a1,...an. P (X) = a0+a1X+...+anXnX an6= 0
P n
A→A
xAP(x)X x
KAK[X]B
K[X]
X2X1X2
X22X X −1
−X1
−X−2
3
X2+X+ 1 = (X−1)(X+2)+3
K K =R C P(X) =
a0+a1X+...+anXnP z0
0z=z0P
X−z0P(X)=(X−z0)Q(X) + R(X)R(X)
X−z0R(X)r0P(X)=(X−z0)Q(X) + r0
X=z0.0 = P(z0) = r0P(X)=(X−z0)Q(X)P
z0X−z0
≥1
n n 1
1
1 0
1
P(X) = a0+a1X+...+anXn
a0, a1. . . anCP(X) = an(X−λ1)(X−λ2)...(X−λn)
λiλ=a+ib b 6= 0 λ=λi
i∈ {1,...,n}P(λ) = 0
0 = P(λ) = a0+a1λ+...+anλn
0=0=a0+a1λ+...+anλn=a0+a1.λ +...+an.λn=a0+a1λ+...+an(λ)n.
λ=a+ib λ =a−ib P λ2λ2, . . . λ =λi
λ(X−λ)(X−λ) = X2−(λ+λ)X+λλ =X2−2aX +(a2+b2)
∆=4a2−4(a2+b2) = −4b2
P1
1R[X]
1
N
{1,2,3,...N},2
3. . . P artieEnti`ere(√N+ 1)