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Mathematics 19 Online
OpenStudy (anonymous):

How to solve this

OpenStudy (anonymous):

If \[a \neq b \] but \[a ^{2} = 5a - 3 \] and \[b ^{2} = 5b - 3 \] then find the equation whose roots are \[\frac{ a }{ b } and \frac{ b }{ a }\]

OpenStudy (anonymous):

@ganeshie8

OpenStudy (vishweshshrimali5):

See: a quadratic equation with roots \(\alpha\) and \(\beta\) is given by : \[ax^2 + bx + c = 0\] iff \[\alpha + \beta = \cfrac{-b}{a}\] \[\alpha \beta = \cfrac{c}{a}\]

OpenStudy (anonymous):

Yes i know that

OpenStudy (vishweshshrimali5):

Gud now here replace alpha and beta by a/b and b/a

OpenStudy (vishweshshrimali5):

Nope

OpenStudy (vishweshshrimali5):

See: \[ax^2 + bx + c = 0\] \[\implies x^2 + \cfrac{b}{a} x + \cfrac{c}{a} = 0\] \[\implies x^2 - \text{(sum of roots)} x + \text{(product of roots)} = 0\]

OpenStudy (anonymous):

But the roots are \[\frac{ a }{ b } and \frac{ b }{a }\]

OpenStudy (vishweshshrimali5):

Here sum of roots will be: \[\cfrac{a}{b} + \cfrac{b}{a} = \cfrac{a^2 + b^2}{ab}\] product of roots will be : \[\cfrac{a}{b} \cfrac{b}{a} = 1\]

OpenStudy (vishweshshrimali5):

Did you get it upto this step ?

OpenStudy (anonymous):

(a+b)^2 -2ab / ab

OpenStudy (vishweshshrimali5):

Yes

OpenStudy (anonymous):

This is the sum of roots sum of roots is :- -b/a Product of roots is :- c/a Substituting that gives what i just wrote

OpenStudy (vishweshshrimali5):

no why are you including this c

OpenStudy (anonymous):

which "c"

OpenStudy (vishweshshrimali5):

|dw:1401282416199:dw|

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