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show-that-P-x-9999-x-8888-x-7777-x-6666-x-5555-x-4444-x-3333-x-2222-x-1111-1-Q-x-9-x-8-x-7-x-6-x-5-x-4-x-3-x-2-x-1-prove-P-is-divisible-by-Q-




Question Number 58246 by tanmay last updated on 20/Apr/19
show that  P=x^(9999) +x^(8888) +x^(7777) +x^(6666) +x^(5555) +x^(4444) +x^(3333) +x^(2222) +x^(1111) +1  Q=x^9 +x^8 +x^7 +x^6 +x^5 +x^4 +x^3 +x^2 +x+1  prove  P  is divisible by Q
$${show}\:{that} \\ $$$${P}={x}^{\mathrm{9999}} +{x}^{\mathrm{8888}} +{x}^{\mathrm{7777}} +{x}^{\mathrm{6666}} +{x}^{\mathrm{5555}} +{x}^{\mathrm{4444}} +{x}^{\mathrm{3333}} +{x}^{\mathrm{2222}} +{x}^{\mathrm{1111}} +\mathrm{1} \\ $$$${Q}={x}^{\mathrm{9}} +{x}^{\mathrm{8}} +{x}^{\mathrm{7}} +{x}^{\mathrm{6}} +{x}^{\mathrm{5}} +{x}^{\mathrm{4}} +{x}^{\mathrm{3}} +{x}^{\mathrm{2}} +{x}+\mathrm{1} \\ $$$${prove}\:\:{P}\:\:{is}\:{divisible}\:{by}\:{Q} \\ $$
Answered by 2pac last updated on 25/Apr/19
p(x)=q(x^(1111) )  let a bee the roots of Q(x)   so ===>a^(10) =1===>a^(1110) =1===a^(1111) =a  so p(a)=Q(a^(1111) )=Q(a)=0  ===>a roots of Q is also root of P so
$${p}\left({x}\right)={q}\left({x}^{\mathrm{1111}} \right) \\ $$$${let}\:{a}\:{bee}\:{the}\:{roots}\:{of}\:{Q}\left({x}\right)\: \\ $$$${so}\:===>{a}^{\mathrm{10}} =\mathrm{1}===>{a}^{\mathrm{1110}} =\mathrm{1}==={a}^{\mathrm{1111}} ={a} \\ $$$${so}\:{p}\left({a}\right)={Q}\left({a}^{\mathrm{1111}} \right)={Q}\left({a}\right)=\mathrm{0} \\ $$$$===>{a}\:{roots}\:{of}\:{Q}\:{is}\:{also}\:{root}\:{of}\:{P}\:{so}\: \\ $$

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