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x-log-3-2-x-1-




Question Number 77631 by Maclaurin Stickker last updated on 08/Jan/20
x^(log_3 (2)) =(√x)+1
$${x}^{{log}_{\mathrm{3}} \left(\mathrm{2}\right)} =\sqrt{{x}}+\mathrm{1} \\ $$
Answered by mr W last updated on 08/Jan/20
log _3 2=log_x  ((√x)+1)  ((ln 2)/(ln 3))=((ln ((√x)+1))/(ln x))  ((ln 2^n )/(ln 3^n ))=((ln ((√x)+1))/(ln x))  ⇒x=3^n   ⇒(√x)+1=2^n   we see the only solution is n=2:  x=3^2 =9  (√x)+1=(√9)+1=4=2^2  ⇒ok  therefore x=9.
$$\mathrm{log}\:_{\mathrm{3}} \mathrm{2}=\mathrm{log}_{{x}} \:\left(\sqrt{{x}}+\mathrm{1}\right) \\ $$$$\frac{\mathrm{ln}\:\mathrm{2}}{\mathrm{ln}\:\mathrm{3}}=\frac{\mathrm{ln}\:\left(\sqrt{{x}}+\mathrm{1}\right)}{\mathrm{ln}\:{x}} \\ $$$$\frac{\mathrm{ln}\:\mathrm{2}^{{n}} }{\mathrm{ln}\:\mathrm{3}^{{n}} }=\frac{\mathrm{ln}\:\left(\sqrt{{x}}+\mathrm{1}\right)}{\mathrm{ln}\:{x}} \\ $$$$\Rightarrow{x}=\mathrm{3}^{{n}} \\ $$$$\Rightarrow\sqrt{{x}}+\mathrm{1}=\mathrm{2}^{{n}} \\ $$$${we}\:{see}\:{the}\:{only}\:{solution}\:{is}\:{n}=\mathrm{2}: \\ $$$${x}=\mathrm{3}^{\mathrm{2}} =\mathrm{9} \\ $$$$\sqrt{{x}}+\mathrm{1}=\sqrt{\mathrm{9}}+\mathrm{1}=\mathrm{4}=\mathrm{2}^{\mathrm{2}} \:\Rightarrow{ok} \\ $$$${therefore}\:{x}=\mathrm{9}. \\ $$

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