The polynomial of degree 5, P(x) has leading coefficient 1, has roots of multiplicity 2 at x=1 and x=0, and a root of multiplicity 1 at x=-3, how do you find a possible formula for P(x)?

1 Answer
Apr 21, 2016

P(x) = x^5+x^4-5x^3+3x^2

Explanation:

Each root corresponds to a linear factor, so we can write:

P(x) = x^2(x-1)^2(x+3)

=x^2(x^2-2x+1)(x+3)

= x^5+x^4-5x^3+3x^2

Any polynomial with these zeros and at least these multiplicities will be a multiple (scalar or polynomial) of this P(x)

Footnote

Strictly speaking, a value of x that results in P(x) = 0 is called a root of P(x) = 0 or a zero of P(x). So the question should really have spoken about the zeros of P(x) or about the roots of P(x) = 0.