Menu Close

Question-190925




Question Number 190925 by sonukgindia last updated on 14/Apr/23
Commented by Frix last updated on 14/Apr/23
x=((1+(√5))/2)
$${x}=\frac{\mathrm{1}+\sqrt{\mathrm{5}}}{\mathrm{2}} \\ $$
Answered by ibrahimabdullayev last updated on 14/Apr/23
  Solution:Ibrahim Abdullayev  (x−(1/x))^(1/2) −(1−(1/x))^(1/2) =((x−1)/x)  (x−(1/x))^(1/2) +(1−(1/x))^(1/2) =x  2(x−(1/x))^(1/2) =((x^2 +x−1)/x)  ((4x^2 −4)/x)=(((x^2 +x−1)^2 )/x^2 )    x^4 −2x^3 −x^2 +2x+1=0  x^2 +(1/x^2 )−2(x−(1/x))−1=0  x−(1/x)=t ⇒ t^2 −2t+1=0 ⇒ t=1  x−(1/x)=1⇒ x^2 −x−1=0 ⇒x=((1+(√5))/2)                   x=((1+(√5))/2)
$$ \\ $$$${Solution}:{Ibrahim}\:{Abdullayev} \\ $$$$\left({x}−\frac{\mathrm{1}}{{x}}\right)^{\frac{\mathrm{1}}{\mathrm{2}}} −\left(\mathrm{1}−\frac{\mathrm{1}}{{x}}\right)^{\frac{\mathrm{1}}{\mathrm{2}}} =\frac{{x}−\mathrm{1}}{{x}} \\ $$$$\left({x}−\frac{\mathrm{1}}{{x}}\right)^{\frac{\mathrm{1}}{\mathrm{2}}} +\left(\mathrm{1}−\frac{\mathrm{1}}{{x}}\right)^{\frac{\mathrm{1}}{\mathrm{2}}} ={x} \\ $$$$\mathrm{2}\left({x}−\frac{\mathrm{1}}{{x}}\right)^{\frac{\mathrm{1}}{\mathrm{2}}} =\frac{{x}^{\mathrm{2}} +{x}−\mathrm{1}}{{x}} \\ $$$$\frac{\mathrm{4}{x}^{\mathrm{2}} −\mathrm{4}}{{x}}=\frac{\left({x}^{\mathrm{2}} +{x}−\mathrm{1}\right)^{\mathrm{2}} }{{x}^{\mathrm{2}} }\: \\ $$$$\:{x}^{\mathrm{4}} −\mathrm{2}{x}^{\mathrm{3}} −{x}^{\mathrm{2}} +\mathrm{2}{x}+\mathrm{1}=\mathrm{0} \\ $$$${x}^{\mathrm{2}} +\frac{\mathrm{1}}{{x}^{\mathrm{2}} }−\mathrm{2}\left({x}−\frac{\mathrm{1}}{{x}}\right)−\mathrm{1}=\mathrm{0} \\ $$$${x}−\frac{\mathrm{1}}{{x}}={t}\:\Rightarrow\:{t}^{\mathrm{2}} −\mathrm{2}{t}+\mathrm{1}=\mathrm{0}\:\Rightarrow\:{t}=\mathrm{1} \\ $$$${x}−\frac{\mathrm{1}}{{x}}=\mathrm{1}\Rightarrow\:{x}^{\mathrm{2}} −{x}−\mathrm{1}=\mathrm{0}\:\Rightarrow{x}=\frac{\mathrm{1}+\sqrt{\mathrm{5}}}{\mathrm{2}} \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:{x}=\frac{\mathrm{1}+\sqrt{\mathrm{5}}}{\mathrm{2}} \\ $$

Leave a Reply

Your email address will not be published. Required fields are marked *