One complex root of a polynomial function is 2 + i. The other complex root is
a) -2 + i
b) 2 – i
c) -2 – i
d) +/-2u
2007-02-26 00:45:07 · 5 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
(2 – i)(2 + i)
=2^2– i^2
=4 –(-1)
=5
The other conjucate pair of this complex root is 2 – i.
2007-02-26 00:52:53 · answer #1 · answered by math freak 3 · 0⤊ 0⤋
You can only be sure that there is another root of 2 - i if the polynomial had all real coefficients. If not there might be a conjugate pair but there might not be. By the way, we normally talk about the roots of equations and the factors of polynomials.
2007-02-26 09:00:05 · answer #2 · answered by mathsmanretired 7 · 0⤊ 0⤋
You need to mention that the polynomial function has real coefficients. In this case, all complex roots appear in conjugates.
2007-02-26 09:26:21 · answer #3 · answered by nayanmange 4 · 0⤊ 0⤋
b. 2-i
2007-02-26 09:02:04 · answer #4 · answered by Anonymous · 0⤊ 0⤋
2-i
Because complex roots occur in conjugate pairs.
To get a number's conjugate, simply reverse the sign of the complex part.
2007-02-26 08:52:46 · answer #5 · answered by shrek 5 · 0⤊ 0⤋