Question

use the given zero to find the remaining zeros of the function:
f(x)= x^4-12x^2-64; zero:-2i
please show me step by step... thanks..

Answer 1

hmm, is that spose to be an imaginary number?

Answer 2

(x+2i)(x-2i) because they come in conjugates:
x^2+ 4
and divide the original by x^2+4

Answer 3

if so, x^4 indicates that the zeros are located 90 degrees from each other i think

Answer 4

-2i, 2, 2i, and -2 would be it if I see it right

Answer 5

so i got x^2-16 so itd be +/- 4

Answer 6

http://www.wolframalpha.com/input/?i=x^4-12x^2-64

Answer 7

oh wait no youre right

Answer 8

no i am right

Answer 9

the way i remember complex zeroes is that the highest degree tell us how to divide the circle;

x^2 would be 360/2
x^3 would be 360/3
x^4 would be 360/4 = 90

since -2i is the same as 270 degrees; we end up on the axises each time

Answer 10

it would be +/- 2i and +/- 4

Answer 11

thats it :)

Answer 12

i still dont understand... :(...

Answer 13

how much of it do you understand tho? so we have something to work from

Answer 14

when you have imaginary zeros, they always come in conjugate pairs such as x+i x-i so you can multiply those together to get a factor. so then you can divide the original polynomial by that factor

Answer 15

not factor... another polynomial. bad wording haha

Answer 16

hihi ok.