Math CentralQuandaries & Queries


Question from Ryan, a student:

What is the fourth degree polynomial function with real coefficients
that has -1,1 and I as zeros and such that f(x)=160


Are the zeros 1, -1 and i where i is the square root of -1? Also you have said that f(x) = 160 and I think the "x" should be some specific number. Can you check this and get back to us?


Ryan replied

I believe the correct answer is x=(160 .5+1) .5
I cannot properly express in email without symbols. But I am assuming you understand.


I don't understand but let's proceed as if the zeros are 1, -1 and i = √-1.

TOne fact you need is that if a polynomial with real coefficients has a complex zero then the complex conjugate is a zero also. Thus in your situation both i and -i are zeros of the polynomial.

Now look at Harley's response to a question from Kristen and see if that helps with your problem.

Write back if you need more assistance,

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