1. a. Write the general polynomial p(x) whose only zeros are 1, 2 and 3, with multiplicity 3, 2 and 1 respectively. What is its degree? b. find p(x) described in part (a)if p(0) = 6.

1 answer

To construct the polynomial \( p(x) \) with the specified zeros and multiplicities, we start with the zeros 1, 2, and 3 corresponding to the multiplicities 3, 2, and 1.

Part a:

The general form of the polynomial can be written as:

\[ p(x) = k(x - 1)^3(x - 2)^2(x - 3)^1 \]

where \( k \) is a constant that will be determined in part (b).

The degree of the polynomial \( p(x) \) can be found by adding the multiplicities of the zeros:

  • The multiplicity of zero 1 is 3.
  • The multiplicity of zero 2 is 2.
  • The multiplicity of zero 3 is 1.

Thus, the degree of the polynomial is:

\[ \text{Degree} = 3 + 2 + 1 = 6 \]

So the degree is 6.

Part b:

Now, we want to find the specific polynomial \( p(x) \) such that \( p(0) = 6 \).

First, we substitute \( x = 0 \) into the polynomial:

\[ p(0) = k(0 - 1)^3(0 - 2)^2(0 - 3)^1 \]

Calculating this gives:

\[ p(0) = k(-1)^3(-2)^2(-3) = k(-1)(4)(-3) = k(12) \]

We are given that \( p(0) = 6 \), thus:

\[ k(12) = 6 \]

To find \( k \):

\[ k = \frac{6}{12} = \frac{1}{2} \]

Now we can write the specific polynomial \( p(x) \):

\[ p(x) = \frac{1}{2}(x - 1)^3(x - 2)^2(x - 3) \]

Therefore, the polynomial \( p(x) \) is:

\[ p(x) = \frac{1}{2}(x - 1)^3(x - 2)^2(x - 3) \]

And the degree is 6.