Find a polynomial function of lowest degree with rational co
Find a polynomial function of lowest degree with rational coefficients that has the given numbers as some of its zeros. 4+1,3
Solution
I hope the zeros are 4+i and 3.
Note: If \'a\' is a zero, the the corresponding zero ix \'x-a\'.
We know that irrational roots always occur in pairs.
So, 4-i is also a zero since 4+i is a zero.
Also 3 is a zero.
So the polynomial is,
P(x) =(x-(4+i)) (x-(4-i)) (x-3)
= (x-4-i)(x-4+i) (x-3)
= ((x-4)2-i2) (x - 3 )
= (x2+16-8x+1)(x-3) (Because i2 = -1)
= (x2-8x+17) (x-3)
= x3-8x2+17x -3x2+24x-51
= x3-11x2+41x -51, which is the required polynomial.
