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If-f-x-1-x-x-4-1-x-4-find-f-5-




Question Number 128132 by I want to learn more last updated on 04/Jan/21
If   f(x  +  (1/x))   =   x^4   +  (1/x^4 ) ,     find  f(5)
Iff(x+1x)=x4+1x4,findf(5)
Answered by Olaf last updated on 04/Jan/21
f(x+(1/x)) = x^4 +(1/x^4 ) = (x^2 +(1/x^2 ))^2 −2  = [(x+(1/x))^2 −2]^2 −2  If u = x+(1/x)  f(u) = (u^2 −2)^2 −2  f(5) = (25−2)^2 −2 = 527
f(x+1x)=x4+1x4=(x2+1x2)22=[(x+1x)22]22Ifu=x+1xf(u)=(u22)22f(5)=(252)22=527

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