Solve the Tricky Equation: Finding x in a Complex Equation

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Homework Statement


find x in the equation:

a = x + 1/x


Homework Equations





The Attempt at a Solution


I sat down and thought it was easy to do, but was terribly schocked at the fact, that I didn't know how to solve this equation. What is the general approach?
 
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aaaa202 said:

Homework Statement


find x in the equation:

a = x + 1/x

Homework Equations



The Attempt at a Solution


I sat down and thought it was easy to do, but was terribly schocked at the fact, that I didn't know how to solve this equation. What is the general approach?
Multiplying both sides by x results in a quadratic equation.
 
If that is 1= x+ (1/x) then multiplying both sides by x gives the quadratic equation [itex]x= x^2+ 1[/itex] which is equivalent to [itex]x^2- x+ 1= 0[/itex]. You will find that it has no real roots. If it is, rather, 1= (x+ 1)/x (in which case you should have used parentheses) you can again multiply both sides by x to get x= x+ 1 which is not true for any value of x.
 
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HallsofIvy said:
If that is 1= x+ (1/x) then multiplying both sides by x gives the quadratic equation [itex]x= x^2+ 1[/itex] which is equivalent to [itex]x^2- x+ 1= 0[/itex]. You will find that it has no real roots.

If it is, rather, 1= (x+ 1)/x (in which case you should have used parentheses) you can again multiply both sides by x to get x= x+ 1 which is not true for any value of x.
If a ≠ 1, then [itex]\displaystyle a=\frac{x+1}{x}[/itex] does have one real root.
 
aaaa202 said:

Homework Statement


find x in the equation:

a = x + 1/x

Homework Equations


The Attempt at a Solution


I sat down and thought it was easy to do, but was terribly schocked at the fact, that I didn't know how to solve this equation. What is the general approach?

[Post cleared by myself]
 
Last edited:
SammyS said:
IMO: I think that since aaaa202 has not come back to post a response, we should probably not be giving a full-blown solution .

Ya, I think you are right, I cleared my response.