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Given-lim-x-5-f-x-a-x-5-8-lim-x-5-x-2-ax-b-f-x-a-1-find-the-value-of-b-23-




Question Number 105383 by bemath last updated on 28/Jul/20
Given  { ((lim_(x→5) ((f(x)−a)/(x−5)) = 8)),((lim_(x→5) ((x^2 −ax+b)/(f(x)−a)) = 1)) :}  find the value of b+23
Given{limx5f(x)ax5=8limx5x2ax+bf(x)a=1findthevalueofb+23
Answered by john santu last updated on 28/Jul/20
(1) lim_(x→5) ((f(x)−a)/(x−5))=8 → { ((f(5)=a)),((f ′(5)=8)) :}  (2) lim_(x→5) ((x^2 −ax+b)/(f(x)−a)) = 1   ⇒25−5f(5)+b = 0; b = 5f(5)−25  ⇒lim_(x→5) ((2x−a)/(f ′(x))) = 1 ; 10−a=f ′(5)  a = 10−f ′(5)=10−8=2  and b = 5f(5)−25 =  5×2−25=−15  we conclude b+23 =  −15+23=8
(1)limx5f(x)ax5=8{f(5)=af(5)=8(2)limx5x2ax+bf(x)a=1255f(5)+b=0;b=5f(5)25limx52xaf(x)=1;10a=f(5)a=10f(5)=108=2andb=5f(5)25=5×225=15weconcludeb+23=15+23=8
Commented by bemath last updated on 28/Jul/20
jooss
jooss

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