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Old September 7th, 2008, 11:56 PM
sqleung sqleung is offline
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Default Abstract Polynomials Question

Hello. I seem to be having a little trouble with this problem regarding quartics so if you could assist me, it would be greatly appreciated:

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A polynomial with real coefficients and two integer zeroes p and q is given as:

P(x) = x^4 + ax^3 + bx^2 + cx - 10

P(x) has a complex zeroes 1 + ki and 1 - ki

\bullet Using p and q, write another expression for a real quadratic factor of P(x) and using this, list the possible values of pq whereby p, q and 1 + ki are the zeroes of P(x)

So far, using sum and product, I wrote it as a quadratic factor:

x^2 - (p + q)x + pq

That means the quartic can be written as (using the real and complex factor):

P(x) = [x^2 - 2x + (1 + k^2)][x^2 - (p + q)x + pq]

Is this right so far?

\bullet Given p + q = -1, show that there's only one possible value for pq and hence, find all the zeroes of P(x)

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If you could help me out here, it would be greatly appreciated.

Thank you.
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