The discussion centers on solving the quadratic equation x^2 - 2x + 4 = 0 to find the value of x1^2 + x2^2. Participants utilized Vieta's theorem to determine that x1 + x2 = 2 and x1 * x2 = 4, acknowledging the absence of real roots due to the presence of complex numbers. The relationship x1^2 + x2^2 = (x1 + x2)^2 - 2x1x2 was confirmed as a valid approach to derive the desired result.
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blunted said:Homework Statement
If the roots of x^2 - 2x + 4 = 0 are x1 and x2, what is x1^2 + x2^2?
Homework Equations
The Attempt at a Solution
I don't think these questions can be answered by solving for x only cause there will be no real root(complex number).
So I found that x1 + x2 = 2 and x1 * x2 = 4 via Vieta's theorem.
And I tried solving it with the quadratic formula but as I said it hasn't got a real root.
Expand (x1 + x2)2 & see what you get.blunted said:How did you get to that equation? :O