use multiplication to find the product that demands the closure property of multiplication of polynomials

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

1 answer

To find the product of the polynomial \((\frac{1}{2}x^2 - 3)(4y^3 + 5x^2)\) and illustrate the closure property of multiplication of polynomials, we will multiply these two polynomials.

Step 1: Distribute each term in the first polynomial with each term in the second polynomial.

\[ \left(\frac{1}{2}x^2 - 3\right)(4y^3 + 5x^2) \]

Step 2: Multiply \(\frac{1}{2}x^2\) by each term in \(4y^3 + 5x^2\):

  1. \(\frac{1}{2}x^2 \cdot 4y^3 = 2x^2y^3\)
  2. \(\frac{1}{2}x^2 \cdot 5x^2 = \frac{5}{2}x^4\)

Step 3: Multiply \(-3\) by each term in \(4y^3 + 5x^2\):

  1. \(-3 \cdot 4y^3 = -12y^3\)
  2. \(-3 \cdot 5x^2 = -15x^2\)

Step 4: Combine all results:

Now we combine all these products:

\[ 2x^2y^3 + \frac{5}{2}x^4 - 12y^3 - 15x^2 \]

Step 5: Organizing the polynomial:

Putting it together, we write the final polynomial as:

\[ \frac{5}{2}x^4 + 2x^2y^3 - 15x^2 - 12y^3 \]

Conclusion:

The result \(\frac{5}{2}x^4 + 2x^2y^3 - 15x^2 - 12y^3\) is indeed a polynomial, which demonstrates the closure property of multiplication of polynomials: when two polynomials are multiplied, the result is also a polynomial.