write a polynomial function with given roots :-
3+i , 2 and -4
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OpenStudy (imstuck):
This will be a fourth degree polynomial. One root is (x - 2), another is (x + 4) another is (x - (3 + i)) and because you have a - (3 + i), you also have to have a + (3 + i).
OpenStudy (imstuck):
So here they are, all in a row!
OpenStudy (driftracer305):
ok
OpenStudy (imstuck):
(x - 2)(x + 4)(x - [3 + i])(x + [3 + i])
OpenStudy (anonymous):
if \(a+bi\) is a root, so is \(a-bi\)
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OpenStudy (anonymous):
Otherwise, the function would not have real coefficients
OpenStudy (anonymous):
Unless this is supposed to be a complex polynomial
OpenStudy (driftracer305):
ahh.........i get it
OpenStudy (imstuck):
So let's multiply those out, 2 sets of parenthesis at a time. Let's work with the first 2, becasue they do not have the imaginary i in them.
OpenStudy (driftracer305):
uhh wait
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OpenStudy (imstuck):
(x - 2)(x + 4) =\[x ^{2}+2x-8\]
OpenStudy (driftracer305):
x^2+2x-8
OpenStudy (driftracer305):
ok gotcha......next thing?
OpenStudy (imstuck):
wait for what? O right! That's right, you got it! Now let'ss do the others.