Polynomials . Find the polynomial with lowest degree having the following zeros : 2 and 2i .
A polynomial has complex roots in pairs of conjugates. As the polynomial has roots 2 and 2i, it also has -2i as a root.
The polynomial is: (x - 2)(x - 2i)(x + 2i)
=> (x - 2)(x^2 - 4i^2)
=> (x - 2)(x^2 + 4)
=> x^3 - 2x^2 + 4x - 8
The required polynomial is x^3 - 2x^2 + 4x - 8
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