Discover answers to your questions with Westonci.ca, the leading Q&A platform that connects you with knowledgeable experts. Ask your questions and receive accurate answers from professionals with extensive experience in various fields on our platform. Connect with a community of professionals ready to help you find accurate solutions to your questions quickly and efficiently.
Sagot :
Certainly! To determine the value of [tex]\(\alpha^3 + \beta^3 + \gamma^3\)[/tex] given that [tex]\(\alpha\)[/tex], [tex]\(\beta\)[/tex], and [tex]\(\gamma\)[/tex] are the zeros of the polynomial [tex]\(x^3 - 5x^2 + 6x - 1\)[/tex], let's follow a step-by-step approach.
### Step 1: Identify the Polynomial Coefficients and Use Vieta's Formulas
The polynomial we are working with is [tex]\(x^3 - 5x^2 + 6x - 1\)[/tex]. By Vieta's formulas, we know that for a polynomial [tex]\(x^3 + px^2 + qx + r\)[/tex], the sum and products of its roots can be expressed in terms of the coefficients:
- The sum of the roots, [tex]\(\alpha + \beta + \gamma\)[/tex], is [tex]\(-(-5) = 5\)[/tex].
- The sum of the product of the roots taken two at a time, [tex]\(\alpha\beta + \beta\gamma + \gamma\alpha\)[/tex], is [tex]\(6\)[/tex].
- The product of the roots, [tex]\(\alpha\beta\gamma\)[/tex], is [tex]\(-(-1) = 1\)[/tex].
So,
[tex]\[ \alpha + \beta + \gamma = 5 \][/tex]
[tex]\[ \alpha\beta + \beta\gamma + \gamma\alpha = 6 \][/tex]
[tex]\[ \alpha\beta\gamma = 1 \][/tex]
### Step 2: Compute the Sum of the Squares of the Roots
Using the identity for the sum of squares of the roots:
[tex]\[ \alpha^2 + \beta^2 + \gamma^2 = (\alpha + \beta + \gamma)^2 - 2(\alpha\beta + \beta\gamma + \gamma\alpha) \][/tex]
Substitute the values:
[tex]\[ \alpha^2 + \beta^2 + \gamma^2 = (5)^2 - 2(6) \][/tex]
[tex]\[ \alpha^2 + \beta^2 + \gamma^2 = 25 - 12 = 13 \][/tex]
### Step 3: Use the Identity for the Sum of the Cubes of the Roots
We use the identity for the sum of the cubes of the roots:
[tex]\[ \alpha^3 + \beta^3 + \gamma^3 = (\alpha + \beta + \gamma)(\alpha^2 + \beta^2 + \gamma^2 - \alpha\beta - \beta\gamma - \gamma\alpha) + 3\alpha\beta\gamma \][/tex]
Substitute the known values:
[tex]\[ \alpha^3 + \beta^3 + \gamma^3 = (5)(13 - 6) + 3(1) \][/tex]
[tex]\[ \alpha^3 + \beta^3 + \gamma^3 = 5 \times 7 + 3 \][/tex]
[tex]\[ \alpha^3 + \beta^3 + \gamma^3 = 35 + 3 = 38 \][/tex]
### Conclusion
Hence, the value of [tex]\(\alpha^3 + \beta^3 + \gamma^3\)[/tex] is:
[tex]\[ \boxed{38} \][/tex]
### Step 1: Identify the Polynomial Coefficients and Use Vieta's Formulas
The polynomial we are working with is [tex]\(x^3 - 5x^2 + 6x - 1\)[/tex]. By Vieta's formulas, we know that for a polynomial [tex]\(x^3 + px^2 + qx + r\)[/tex], the sum and products of its roots can be expressed in terms of the coefficients:
- The sum of the roots, [tex]\(\alpha + \beta + \gamma\)[/tex], is [tex]\(-(-5) = 5\)[/tex].
- The sum of the product of the roots taken two at a time, [tex]\(\alpha\beta + \beta\gamma + \gamma\alpha\)[/tex], is [tex]\(6\)[/tex].
- The product of the roots, [tex]\(\alpha\beta\gamma\)[/tex], is [tex]\(-(-1) = 1\)[/tex].
So,
[tex]\[ \alpha + \beta + \gamma = 5 \][/tex]
[tex]\[ \alpha\beta + \beta\gamma + \gamma\alpha = 6 \][/tex]
[tex]\[ \alpha\beta\gamma = 1 \][/tex]
### Step 2: Compute the Sum of the Squares of the Roots
Using the identity for the sum of squares of the roots:
[tex]\[ \alpha^2 + \beta^2 + \gamma^2 = (\alpha + \beta + \gamma)^2 - 2(\alpha\beta + \beta\gamma + \gamma\alpha) \][/tex]
Substitute the values:
[tex]\[ \alpha^2 + \beta^2 + \gamma^2 = (5)^2 - 2(6) \][/tex]
[tex]\[ \alpha^2 + \beta^2 + \gamma^2 = 25 - 12 = 13 \][/tex]
### Step 3: Use the Identity for the Sum of the Cubes of the Roots
We use the identity for the sum of the cubes of the roots:
[tex]\[ \alpha^3 + \beta^3 + \gamma^3 = (\alpha + \beta + \gamma)(\alpha^2 + \beta^2 + \gamma^2 - \alpha\beta - \beta\gamma - \gamma\alpha) + 3\alpha\beta\gamma \][/tex]
Substitute the known values:
[tex]\[ \alpha^3 + \beta^3 + \gamma^3 = (5)(13 - 6) + 3(1) \][/tex]
[tex]\[ \alpha^3 + \beta^3 + \gamma^3 = 5 \times 7 + 3 \][/tex]
[tex]\[ \alpha^3 + \beta^3 + \gamma^3 = 35 + 3 = 38 \][/tex]
### Conclusion
Hence, the value of [tex]\(\alpha^3 + \beta^3 + \gamma^3\)[/tex] is:
[tex]\[ \boxed{38} \][/tex]
We hope this was helpful. Please come back whenever you need more information or answers to your queries. We hope you found this helpful. Feel free to come back anytime for more accurate answers and updated information. Stay curious and keep coming back to Westonci.ca for answers to all your burning questions.