Use multiplication to find the product that demonstrates the Closure Property of multiplication of polynomials.

(1/2 x^2 – 3)(4y^3 + 5x^2)

1 answer

To demonstrate the Closure Property of multiplication of polynomials, we will multiply the two given polynomials:

\[ (1/2 x^2 - 3)(4y^3 + 5x^2) \]

We will use the distributive property (also known as the FOIL method for binomials) to perform this multiplication:

  1. Multiply each term in the first polynomial by each term in the second polynomial.

\[ (1/2 x^2)(4y^3) + (1/2 x^2)(5x^2) - (3)(4y^3) - (3)(5x^2) \]

  1. Now calculate each of these products:
  • First term: \[ (1/2 x^2)(4y^3) = 2x^2y^3 \]

  • Second term: \[ (1/2 x^2)(5x^2) = \frac{5}{2} x^4 \]

  • Third term: \[ (-3)(4y^3) = -12y^3 \]

  • Fourth term: \[ (-3)(5x^2) = -15x^2 \]

  1. Now combine all the computed terms: \[ 2x^2y^3 + \frac{5}{2} x^4 - 12y^3 - 15x^2 \]

  2. Rewrite the expression in standard polynomial form (i.e., arrange by decreasing degree): \[ \frac{5}{2} x^4 + 2x^2y^3 - 15x^2 - 12y^3 \]

From this multiplication, we can see that the product itself is a polynomial, which demonstrates the Closure Property of multiplication of polynomials. The polynomial remains within the set of polynomials after multiplication.

Thus, the final result of multiplying the two polynomials is: \[ \frac{5}{2} x^4 + 2x^2y^3 - 15x^2 - 12y^3 \]