Complex Expression 69707D
1. **State the problem:** Simplify or analyze the expression $2x(x - i)^2(x - \sqrt{3i})^2$ where $i$ is the imaginary unit.
2. **Recall important rules:**
- The imaginary unit $i$ satisfies $i^2 = -1$.
- To simplify powers, expand binomials carefully.
3. **Expand $(x - i)^2$:**
$$(x - i)^2 = x^2 - 2ix + i^2 = x^2 - 2ix - 1$$
4. **Expand $(x - \sqrt{3i})^2$:**
First, note $\sqrt{3i}$ is a complex number; let $a = \sqrt{3i}$.
$$(x - a)^2 = x^2 - 2ax + a^2$$
Calculate $a^2 = 3i$.
So,
$$(x - \sqrt{3i})^2 = x^2 - 2x\sqrt{3i} + 3i$$
5. **Rewrite the original expression:**
$$2x (x^2 - 2ix - 1)(x^2 - 2x\sqrt{3i} + 3i)$$
6. **Multiply the two quadratics:**
Let $A = x^2 - 2ix - 1$, $B = x^2 - 2x\sqrt{3i} + 3i$.
Calculate $AB$:
$$AB = x^2(x^2 - 2x\sqrt{3i} + 3i) - 2ix(x^2 - 2x\sqrt{3i} + 3i) - 1(x^2 - 2x\sqrt{3i} + 3i)$$
Expand each term:
- $x^2 \cdot x^2 = x^4$
- $x^2 \cdot (-2x\sqrt{3i}) = -2x^3\sqrt{3i}$
- $x^2 \cdot 3i = 3ix^2$
- $-2ix \cdot x^2 = -2ix^3$
- $-2ix \cdot (-2x\sqrt{3i}) = +4ix^2\sqrt{3i}$
- $-2ix \cdot 3i = -6i^2 x$
- $-1 \cdot x^2 = -x^2$
- $-1 \cdot (-2x\sqrt{3i}) = +2x\sqrt{3i}$
- $-1 \cdot 3i = -3i$
7. **Simplify terms:**
Recall $i^2 = -1$, so $-6i^2 x = -6(-1) x = 6x$.
Group terms:
- $x^4$
- $-2x^3\sqrt{3i} - 2ix^3$
- $3ix^2 + 4ix^2\sqrt{3i} - x^2$
- $6x + 2x\sqrt{3i}$
- $-3i$
8. **Final expression:**
$$2x \left[x^4 + (-2x^3\sqrt{3i} - 2ix^3) + (3ix^2 + 4ix^2\sqrt{3i} - x^2) + (6x + 2x\sqrt{3i}) - 3i \right]$$
This is the fully expanded form with complex terms.
**Answer:**
$$2x \left[x^4 - 2x^3\sqrt{3i} - 2ix^3 + 3ix^2 + 4ix^2\sqrt{3i} - x^2 + 6x + 2x\sqrt{3i} - 3i \right]$$