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If-x-a-1-a-1-a-1-a-1-and-y-a-1-a-1-a-1-a-1-then-show-that-x-2-xy-y-2-x-2-xy-y-2-4a-2-3-4a-




Question Number 202604 by MATHEMATICSAM last updated on 30/Dec/23
If x = (((√(a + 1)) + (√(a − 1)))/( (√(a + 1)) − (√(a − 1)))) and   y = (((√(a + 1)) − (√(a − 1)))/( (√(a + 1)) + (√(a − 1)))) then show that  ((x^2  − xy + y^2 )/(x^2  + xy + y^2 )) = ((4a^2  − 3)/(4a^2  − 1)) .
Ifx=a+1+a1a+1a1andy=a+1a1a+1+a1thenshowthatx2xy+y2x2+xy+y2=4a234a21.
Answered by Rasheed.Sindhi last updated on 30/Dec/23
x = (((√(a + 1)) + (√(a − 1)) )/( (√(a + 1)) − (√(a − 1)))) =(A/B)  , y=(B/A)  A+B=((√(a + 1)) + (√(a − 1)) )+((√(a + 1)) − (√(a − 1)) )              =2(√(a+1))    AB=((√(a + 1)) + (√(a − 1)) )((√(a + 1)) − (√(a − 1)) )           =((√(a + 1)) )^2  −( (√(a − 1)) )^2 =(a+1)−(a−1)=2     ((x^2  − xy + y^2 )/(x^2  + xy + y^2 )) = ((4a^2  − 3)/(4a^2  − 1))  lhs:((x^2  − xy + y^2 )/(x^2  + xy + y^2 ))=(((x+y)^2 −3xy)/((x+y)^2 −xy))                x+y=(A/B)+(B/A)=((A^2 +B^2 )/(AB))=(((A+B)^2 −2AB)/(AB))                =((( 2(√(a+1)) )^2 −2(2))/2)=2(a+1)−2=2a                 xy=(A/B)×(B/A)=1       =(((2a)^2 −3(1))/((2a)^2 −(1)))=((4a^2 −3)/(4a^2 −1))=rhs
x=a+1+a1a+1a1=AB,y=BAA+B=(a+1+a1)+(a+1a1)=2a+1AB=(a+1+a1)(a+1a1)=(a+1)2(a1)2=(a+1)(a1)=2x2xy+y2x2+xy+y2=4a234a21lhs:x2xy+y2x2+xy+y2=(x+y)23xy(x+y)2xyx+y=AB+BA=A2+B2AB=(A+B)22ABAB=(2a+1)22(2)2=2(a+1)2=2axy=AB×BA=1=(2a)23(1)(2a)2(1)=4a234a21=rhs

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