Friday, July 5, 2013

Determine a polynomial function of lowest degree with rational coefficients that has the roots 3+2i, 3-2i , -1 (multiplicity 2). Can someone help and exlain to me how to solve this?

Multiplicity 2 tells us that the root -1 occurs twice, so 


%28x-%28-1%29%29%28x-%28-1%29%29+ 

i.e. 


%28x%2B1%29%5E2 


Therefore the least degree would be 4: 
P%28x%29+=%28x-%283%2B2i%29%29%28x-%283-2i%29%29%28x%2B1%29%5E2 


:)

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