IDNLearn.com offers expert insights and community wisdom to answer your queries. Discover in-depth and trustworthy answers from our extensive network of knowledgeable professionals.
Sagot :
To determine which of the given terms can appear in the expansion of [tex]\((2a + 4b)^8\)[/tex], we need to understand the binomial expansion theorem. The theorem states that the general term in the expansion of [tex]\((x + y)^n\)[/tex] is given by:
[tex]\[ \binom{n}{k} x^{n-k} y^k \][/tex]
where [tex]\(\binom{n}{k}\)[/tex] is the binomial coefficient.
For our specific problem, [tex]\(n = 8\)[/tex], [tex]\(x = 2a\)[/tex], and [tex]\(y = 4b\)[/tex].
The general term in the expansion of [tex]\((2a + 4b)^8\)[/tex] will therefore be of the form:
[tex]\[ \binom{8}{k} \cdot (2a)^{8-k} \cdot (4b)^k \][/tex]
Simplifying, this becomes:
[tex]\[ \binom{8}{k} \cdot 2^{8-k} \cdot a^{8-k} \cdot 4^k \cdot b^k \][/tex]
[tex]\[ \binom{8}{k} \cdot 2^{8-k} \cdot 4^k \cdot a^{8-k} \cdot b^k \][/tex]
To combine the powers of 2, we note that [tex]\(4^k = (2^2)^k = 2^{2k}\)[/tex]:
[tex]\[ \binom{8}{k} \cdot 2^{8-k} \cdot 2^{2k} \cdot a^{8-k} \cdot b^k \][/tex]
[tex]\[ \binom{8}{k} \cdot 2^{8-k+2k} \cdot a^{8-k} \cdot b^k \][/tex]
[tex]\[ \binom{8}{k} \cdot 2^{8+k} \cdot a^{8-k} \cdot b^k \][/tex]
We are interested in the exponents of [tex]\(a\)[/tex] and [tex]\(b\)[/tex]. For a term [tex]\(a^m b^n\)[/tex] to be in the expansion, [tex]\((8-k)\)[/tex] must equal [tex]\(m\)[/tex] and [tex]\(k\)[/tex] must equal [tex]\(n\)[/tex]. Importantly, [tex]\(k\)[/tex] must be an integer between 0 and 8 (inclusive) because [tex]\(k\)[/tex] ranges from 0 to 8.
Let's check the given terms:
1. [tex]\(a^2 b^3\)[/tex]:
- [tex]\(a\)[/tex] has exponent [tex]\(2\)[/tex]: [tex]\(8 - k = 2\)[/tex] gives [tex]\(k = 6\)[/tex].
- [tex]\(b\)[/tex] has exponent [tex]\(3\)[/tex]: [tex]\(k = 3\)[/tex].
- [tex]\(k\)[/tex] values do not match, so this term is not possible.
2. [tex]\(a^8\)[/tex]:
- [tex]\(a\)[/tex] has exponent [tex]\(8\)[/tex]: [tex]\(8 - k = 8\)[/tex] gives [tex]\(k = 0\)[/tex].
- [tex]\(b\)[/tex] has exponent [tex]\(0\)[/tex]: [tex]\(k = 0\)[/tex].
- The [tex]\(k\)[/tex] values match, so this term is possible.
3. [tex]\(a^5 b^3\)[/tex]:
- [tex]\(a\)[/tex] has exponent [tex]\(5\)[/tex]: [tex]\(8 - k = 5\)[/tex] gives [tex]\(k = 3\)[/tex].
- [tex]\(b\)[/tex] has exponent [tex]\(3\)[/tex]: [tex]\(k = 3\)[/tex].
- The [tex]\(k\)[/tex] values match, so this term is possible.
4. [tex]\(a b^8\)[/tex]:
- [tex]\(a\)[/tex] has exponent [tex]\(1\)[/tex]: [tex]\(8 - k = 1\)[/tex] gives [tex]\(k = 7\)[/tex].
- [tex]\(b\)[/tex] has exponent [tex]\(8\)[/tex]: [tex]\(k = 8\)[/tex].
- [tex]\(k\)[/tex] values do not match, so this term is not possible.
5. [tex]\(a^3 b^5\)[/tex]:
- [tex]\(a\)[/tex] has exponent [tex]\(3\)[/tex]: [tex]\(8 - k = 3\)[/tex] gives [tex]\(k = 5\)[/tex].
- [tex]\(b\)[/tex] has exponent [tex]\(5\)[/tex]: [tex]\(k = 5\)[/tex].
- The [tex]\(k\)[/tex] values match, so this term is possible.
6. [tex]\(a^7 b\)[/tex]:
- [tex]\(a\)[/tex] has exponent [tex]\(7\)[/tex]: [tex]\(8 - k = 7\)[/tex] gives [tex]\(k = 1\)[/tex].
- [tex]\(b\)[/tex] has exponent [tex]\(1\)[/tex]: [tex]\(k = 1\)[/tex].
- The [tex]\(k\)[/tex] values match, so this term is possible.
7. [tex]\(a^6 b^5\)[/tex]:
- [tex]\(a\)[/tex] has exponent [tex]\(6\)[/tex]: [tex]\(8 - k = 6\)[/tex] gives [tex]\(k = 2\)[/tex].
- [tex]\(b\)[/tex] has exponent [tex]\(5\)[/tex]: [tex]\(k = 5\)[/tex].
- [tex]\(k\)[/tex] values do not match, so this term is not possible.
8. [tex]\(b^8\)[/tex]:
- [tex]\(a\)[/tex] has exponent [tex]\(0\)[/tex]: [tex]\(8 - k = 0\)[/tex] gives [tex]\(k = 8\)[/tex].
- [tex]\(b\)[/tex] has exponent [tex]\(8\)[/tex]: [tex]\(k = 8\)[/tex].
- The [tex]\(k\)[/tex] values match, so this term is possible.
The possible terms in the expansion of [tex]\((2a + 4b)^8\)[/tex] are:
[tex]\[ a^8, a^5 b^3, a^3 b^5, a^7 b, b^8 \][/tex]
[tex]\[ \binom{n}{k} x^{n-k} y^k \][/tex]
where [tex]\(\binom{n}{k}\)[/tex] is the binomial coefficient.
For our specific problem, [tex]\(n = 8\)[/tex], [tex]\(x = 2a\)[/tex], and [tex]\(y = 4b\)[/tex].
The general term in the expansion of [tex]\((2a + 4b)^8\)[/tex] will therefore be of the form:
[tex]\[ \binom{8}{k} \cdot (2a)^{8-k} \cdot (4b)^k \][/tex]
Simplifying, this becomes:
[tex]\[ \binom{8}{k} \cdot 2^{8-k} \cdot a^{8-k} \cdot 4^k \cdot b^k \][/tex]
[tex]\[ \binom{8}{k} \cdot 2^{8-k} \cdot 4^k \cdot a^{8-k} \cdot b^k \][/tex]
To combine the powers of 2, we note that [tex]\(4^k = (2^2)^k = 2^{2k}\)[/tex]:
[tex]\[ \binom{8}{k} \cdot 2^{8-k} \cdot 2^{2k} \cdot a^{8-k} \cdot b^k \][/tex]
[tex]\[ \binom{8}{k} \cdot 2^{8-k+2k} \cdot a^{8-k} \cdot b^k \][/tex]
[tex]\[ \binom{8}{k} \cdot 2^{8+k} \cdot a^{8-k} \cdot b^k \][/tex]
We are interested in the exponents of [tex]\(a\)[/tex] and [tex]\(b\)[/tex]. For a term [tex]\(a^m b^n\)[/tex] to be in the expansion, [tex]\((8-k)\)[/tex] must equal [tex]\(m\)[/tex] and [tex]\(k\)[/tex] must equal [tex]\(n\)[/tex]. Importantly, [tex]\(k\)[/tex] must be an integer between 0 and 8 (inclusive) because [tex]\(k\)[/tex] ranges from 0 to 8.
Let's check the given terms:
1. [tex]\(a^2 b^3\)[/tex]:
- [tex]\(a\)[/tex] has exponent [tex]\(2\)[/tex]: [tex]\(8 - k = 2\)[/tex] gives [tex]\(k = 6\)[/tex].
- [tex]\(b\)[/tex] has exponent [tex]\(3\)[/tex]: [tex]\(k = 3\)[/tex].
- [tex]\(k\)[/tex] values do not match, so this term is not possible.
2. [tex]\(a^8\)[/tex]:
- [tex]\(a\)[/tex] has exponent [tex]\(8\)[/tex]: [tex]\(8 - k = 8\)[/tex] gives [tex]\(k = 0\)[/tex].
- [tex]\(b\)[/tex] has exponent [tex]\(0\)[/tex]: [tex]\(k = 0\)[/tex].
- The [tex]\(k\)[/tex] values match, so this term is possible.
3. [tex]\(a^5 b^3\)[/tex]:
- [tex]\(a\)[/tex] has exponent [tex]\(5\)[/tex]: [tex]\(8 - k = 5\)[/tex] gives [tex]\(k = 3\)[/tex].
- [tex]\(b\)[/tex] has exponent [tex]\(3\)[/tex]: [tex]\(k = 3\)[/tex].
- The [tex]\(k\)[/tex] values match, so this term is possible.
4. [tex]\(a b^8\)[/tex]:
- [tex]\(a\)[/tex] has exponent [tex]\(1\)[/tex]: [tex]\(8 - k = 1\)[/tex] gives [tex]\(k = 7\)[/tex].
- [tex]\(b\)[/tex] has exponent [tex]\(8\)[/tex]: [tex]\(k = 8\)[/tex].
- [tex]\(k\)[/tex] values do not match, so this term is not possible.
5. [tex]\(a^3 b^5\)[/tex]:
- [tex]\(a\)[/tex] has exponent [tex]\(3\)[/tex]: [tex]\(8 - k = 3\)[/tex] gives [tex]\(k = 5\)[/tex].
- [tex]\(b\)[/tex] has exponent [tex]\(5\)[/tex]: [tex]\(k = 5\)[/tex].
- The [tex]\(k\)[/tex] values match, so this term is possible.
6. [tex]\(a^7 b\)[/tex]:
- [tex]\(a\)[/tex] has exponent [tex]\(7\)[/tex]: [tex]\(8 - k = 7\)[/tex] gives [tex]\(k = 1\)[/tex].
- [tex]\(b\)[/tex] has exponent [tex]\(1\)[/tex]: [tex]\(k = 1\)[/tex].
- The [tex]\(k\)[/tex] values match, so this term is possible.
7. [tex]\(a^6 b^5\)[/tex]:
- [tex]\(a\)[/tex] has exponent [tex]\(6\)[/tex]: [tex]\(8 - k = 6\)[/tex] gives [tex]\(k = 2\)[/tex].
- [tex]\(b\)[/tex] has exponent [tex]\(5\)[/tex]: [tex]\(k = 5\)[/tex].
- [tex]\(k\)[/tex] values do not match, so this term is not possible.
8. [tex]\(b^8\)[/tex]:
- [tex]\(a\)[/tex] has exponent [tex]\(0\)[/tex]: [tex]\(8 - k = 0\)[/tex] gives [tex]\(k = 8\)[/tex].
- [tex]\(b\)[/tex] has exponent [tex]\(8\)[/tex]: [tex]\(k = 8\)[/tex].
- The [tex]\(k\)[/tex] values match, so this term is possible.
The possible terms in the expansion of [tex]\((2a + 4b)^8\)[/tex] are:
[tex]\[ a^8, a^5 b^3, a^3 b^5, a^7 b, b^8 \][/tex]
We greatly appreciate every question and answer you provide. Keep engaging and finding the best solutions. This community is the perfect place to learn and grow together. IDNLearn.com is dedicated to providing accurate answers. Thank you for visiting, and see you next time for more solutions.