Chứng minh rằng: \(x^{4n+2}+2x^{2n+1}+1⋮\left(x+1\right)^2\)
Chứng minh rằng: \(\left(x^{4n+2}+2x^{2n+1}+1\right)⋮\left(x^2+2x+1\right)\)
n thuộc N
B=x^2 +2x +1 =(x+1)^2
\(A=x^{4n+2}+2.x^{2n+1}+1=\left(x^{2n+1}\right)^2+2.\left(x^{2n+1}\right)+1=\left(x^{2n+1}+1\right)^2\)
\(\dfrac{A}{B}=\left(\dfrac{x^{2n+1}+1}{x+1}\right)^2\)
với n =0 đúng
n >0 =>2n+1 >=3
=> x^(2n+1) =(x+1).g(x) => dpcm
Chứng minh rằng: \(\left(x^{4n+2}+2x^{2n+1}+1\right)⋮\left(x^2+2x+1\right)\)
Ta có :
\(x^{4n+2}+2x^{2n+1}+1=\left(x^{2n+1}\right)^2+2x^{2n+1}+1==\left(x^{2n+1}+1\right)^2\)
Vì \(x^{2n+1}+1⋮x+1\forall x;n\in Z\) nên \(\left(x^{2n+1}+1\right)^2⋮\left(x+1\right)^2=\forall x;n\in Z\)
Hay \(x^{4n+2}+2x^{2n+1}+1⋮x^2+2x+1\)
Chứng minh rằng: \(x^{4n+2}+2x^{2n+1}+1⋮\left(x+1\right)^2\)
Chứng minh rằng:
a. \(x^{10}-10x+9\)chia hết cho \(x^2-2x+1\)
b. \(\left(x+1\right)^{4n+2}+\left(x-1\right)^{4n-2}\)chia hết cho \(x^2+1\)
c. \(\left(x+1\right)^{2n}-x^{2n}-2x-1\)chia hết cho \(x\left(x+1\right)\left(2x+1\right)\)
Bạn nào giải nhanh đúng mình tick cho nha ^ ^.
Chứng minh rằng: \(f\left(x\right)⋮g\left(x\right)\) biết: \(f\left(x\right)=\left(x+1\right)^{2n}-x^{4n}-2x+1\)
\(g\left(x\right)=x.\left(x+1\right).\left(2x+1\right)\) với n thuộc N
Chứng minh rằng: \(f\left(x\right)⋮g\left(x\right)\) biết:
\(f\left(x\right)=\left(x+1\right)^{2n}-x^{4n}-2x+1\)
\(g\left(x\right)=x.\left(x+1\right).\left(2x+1\right)\) với n thuộc N
CMR: với mọi số tự nhiên n :
a) \(\left(x+1\right)^{2n}-x^{2n}-2x-1\) chia hết cho \(x\left(x+1\right)\left(2x+1\right)\)
b) \(x^{4n+2}+2x^{2n+1}+1\) chia hết cho \(\left(x+1\right)^2\)
c) \(\left(x+1\right)^{4n+2}+\left(x-1\right)^{4n+2}\) chia hết cho \(x^2+1\)
chứng minh rằng với mọi số tự n:
a) (x+1)^2n - x^2n - 2x - 1 chia hết cho x(x+1)(2x+1)
b) x^4n+2 +2x^n+1 + 1 chia hết cho (x+1)^2
Chứng minh rằng
a, \(\left(2n-3\right).n-2n.\left(n+2\right)⋮7\forall n\in Z\)
b, \(n.\left(2n-3\right)-2n.\left(n+1\right)⋮5\forall n\in Z\)
Rút gọn
a, (3x-5) . (2x+11) - (2x+3) . (3x+7)
b, (x+2) . (2x2-3x+4) - (x2-1) . (2x+1)
c, 3x2 .(x2+2) + 4x. (x2-1) - (x2+2x+3) . (3x2-2x+1)
\(a,\left(2x-3\right)n-2n\left(n+2\right)\)
\(=n\left(2x-3-2n-4\right)\)
\(=-7n\)
Vì \(-7⋮7\Rightarrow-7n⋮7\) => ĐPCM
\(b,n\left(2n-3\right)-2n\left(n+1\right)\)
\(=n\left(2n-3-2n-2\right)\)
\(=-5n⋮5\) (ĐPCM)
Rút gọn
\(a,\left(3x-5\right)\left(2x+11\right)-\left(2x+3\right)\left(3x+7\right)\)
\(=6x^2+33x-10x-55-6x^2-14x-9x-21\)
\(=-76\)
\(b,\left(x+2\right)\left(2x^2-3x+4\right)-\left(x^2-1\right)\left(2x+1\right)\)
\(=2x^3-3x^2+4x+4x^2-6x+8-2x^3-x^2+2x+1\)
\(=9\)
\(c,3x^2\left(x^2+2\right)+4x\left(x^2-1\right)-\left(x^2+2x+3\right)\left(3x^2-2x+1\right)\)
\(=3x^4+6x^2+4x^3-4x-3x^4+2x^3-x^2-6x^3+4x^2-2x-9x^2+6x-3\)
= -3