# Real Roots

• Feb 21st 2009, 12:11 PM
Real Roots
Hi! I've tried to solve this question, but I came to the conclusion that I couldn't so I gave up! I hope you can help me with this one :)

The equation x^2 - 2kx + 1 = 0 has two distinct real roots. Find the set of all possible values of k.

I would appreciate your help :)

Thanks,
Amine.
• Feb 21st 2009, 12:14 PM
running-gag
Hi

The discriminant is $\Delta = (-2k)^2-4 = 4(k^2-1)$

The equation $x^2 - 2kx + 1 = 0$ has two distinct real roots if $\Delta > 0$

Can you go on ?
• Feb 21st 2009, 12:22 PM
Does the final answer give 1/2(x + 1/x)?
• Feb 21st 2009, 12:30 PM
running-gag
Quote: