Monkeyseat
Full Member
- Joined
- Jul 3, 2005
- Messages
- 298
Find the positive roots of the equation:
x^2 + (4/x^2) = 5
I know it's 1 and 2 but can't prove it. I didn't know whether to try and solve it as x^2 + 4x^-2 - 5 = 0 or multiply both sides by x^2 i.e.:
x^4 + 4 = 5x^2
x^4 - 5x^2 = -4
x^2(x^2 - 5) = -4
x^2 = -4 or x^2 - 5 = -4 ???
But that's wrong...
Anyway, thanks for any help.
x^2 + (4/x^2) = 5
I know it's 1 and 2 but can't prove it. I didn't know whether to try and solve it as x^2 + 4x^-2 - 5 = 0 or multiply both sides by x^2 i.e.:
x^4 + 4 = 5x^2
x^4 - 5x^2 = -4
x^2(x^2 - 5) = -4
x^2 = -4 or x^2 - 5 = -4 ???
But that's wrong...
Anyway, thanks for any help.