Question

Срочноо!!! x^4+1/x^4 при а)x+1/x=3; b)x-1/x=5

Answer 1

$left(xpmdfrac1xright)^4=x^4pm4x^2+6pmdfrac4{x^2}+dfrac1{x^4}\ x^4+dfrac1{x^4}=left(xpmdfrac1xright)^4mp4left(x^2+dfrac1{x^2}right)-6\ x^4+dfrac1{x^4}=left(xpmdfrac1xright)^4mp4left(xpmdfrac1{x}right)^2+8-6\ a);x^4+dfrac1{x^4}=3^4-4cdot3^2+8-6=47\ b);x^4+dfrac1{x^4}=5^4+4cdot5^2+8-6=727$