find the constant term in the expansion of (x-2/x)^4 x (x^2+2/x)^3

To find the constant term in the expansion of the expression \((x - \frac{2}{x})^4 \times (x^2 + \frac{2}{x})^3\), we'll first expand each part and then identify the term that has no \(x\) in it.

### Step 1: Expand \((x - \frac{2}{x})^4\)
We use the binomial expansion formula:

\[
(a + b)^n = \sum_{k=0}^{n} \binom{n}{k} a^{n-k} b^k
\]

For \((x - \frac{2}{x})^4\), we have \(a = x\) and \(b = -\frac{2}{x}\), so:

\[
(x - \frac{2}{x})^4 = \sum_{k=0}^{4} \binom{4}{k} x^{4-k} \left(-\frac{2}{x}\right)^k
\]

Simplifying each term:

\[
\begin{aligned}
k = 0: & \quad \binom{4}{0} x^4 \left(-\frac{2}{x}\right)^0 = x^4 \\
k = 1: & \quad \binom{4}{1} x^3 \left(-\frac{2}{x}\right) = -8x^2 \\
k = 2: & \quad \binom{4}{2} x^2 \left(-\frac{2}{x}\right)^2 = 24x^0 = 24 \\
k = 3: & \quad \binom{4}{3} x^1 \left(-\frac{2}{x}\right)^3 = -32\frac{1}{x^2} \\
k = 4: & \quad \binom{4}{4} x^0 \left(-\frac{2}{x}\right)^4 = 16\frac{1}{x^4} \\
\end{aligned}
\]

So:

\[
(x - \frac{2}{x})^4 = x^4 - 8x^2 + 24 - \frac{32}{x^2} + \frac{16}{x^4}
\]

### Step 2: Expand \((x^2 + \frac{2}{x})^3\)
Again, using the binomial expansion formula:

\[
(x^2 + \frac{2}{x})^3 = \sum_{k=0}^{3} \binom{3}{k} (x^2)^{3-k} \left(\frac{2}{x}\right)^k
\]

Simplifying each term:

\[
\begin{aligned}
k = 0: & \quad \binom{3}{0} x^6 \left(\frac{2}{x}\right)^0 = x^6 \\
k = 1: & \quad \binom{3}{1} x^4 \left(\frac{2}{x}\right) = 6x^3 \\
k = 2: & \quad \binom{3}{2} x^2 \left(\frac{2}{x}\right)^2 = 12x^0 = 12 \\
k = 3: & \quad \binom{3}{3} x^0 \left(\frac{2}{x}\right)^3 = \frac{8}{x^3} \\
\end{aligned}
\]

So:

\[
(x^2 + \frac{2}{x})^3 = x^6 + 6x^3 + 12 + \frac{8}{x^3}
\]

### Step 3: Multiply the Expansions
Now multiply the two expansions together and identify the constant term (which has no \(x\) in it).

\[
\begin{aligned}
(x^4 - 8x^2 + 24 - \frac{32}{x^2} + \frac{16}{x^4}) \times (x^6 + 6x^3 + 12 + \frac{8}{x^3})
\end{aligned}
\]

To find the constant term, we only consider pairs of terms from each expansion that will result in \(x^0\):

\[
\begin{aligned}
\text{From } 24 \times 12 & : \text{ } 24 \times 12 = 288 \\
\text{From } -8x^2 \times \frac{8}{x^3} & : \text{ } -8 \times 8x^{-1} = 0 \text{ (no constant term)} \\
\text{From } x^4 \times \frac{16}{x^4} & : \text{ } 1 \times 16 = 16 \\
\text{From } -32/x^2 \times x^6/x^4 & : \text{ }  -32 
\end{aligned}
\]

Thus, the constant term is:

\[
288 + 16 = \textbf{304}
\]

### Final Answer:
The constant term in the expansion is **304**.

Would you like further details or have any questions?

---

Here are 5 related questions:

1. How do you find the middle term in a binomial expansion?
2. What is the general term in the binomial expansion of \((a + b)^n\)?
3. How can you apply the binomial theorem to expand \((1 + x)^{1/2}\)?
4. What are the properties of binomial coefficients?
5. How do negative exponents affect binomial expansions?

**Tip:** When expanding binomials, carefully track each term's exponent to correctly combine like terms and find specific terms such as constants.

Learn how to find the constant term in the expansion of (x - 2/x)^4 * (x^2 + 2/x)^3 using binomial expansion techniques. This problem covers detailed steps in expanding binomials and identifying specific terms. Suitable for advanced high school students.

Math Problem Statement

Solution

Ask a new question for Free

By Image

Math Problem Analysis

Mathematical Concepts

Formulas

Theorems

Suitable Grade Level

Related Recommendation