Complex Exponential Equation
1. **State the problem:** Given the equation
$$(1a + 2i + 152) \left( \frac{-11 + 21}{5} \right) = (-2 - 4i) \left( \frac{(-6 + 2i)^n}{5} - 1 \right)$$
Solve for $n$.
2. **Simplify constants:** Calculate the fraction
$$\frac{-11 + 21}{5} = \frac{10}{5} = 2$$
So the equation becomes:
$$(1a + 2i + 152) \times 2 = (-2 - 4i) \left( \frac{(-6 + 2i)^n}{5} - 1 \right)$$
3. **Rewrite the left side:**
$$2(1a + 2i + 152) = 2a + 4i + 304$$
4. **Divide both sides by $-2 - 4i$ to isolate the right term:**
$$\frac{2a + 4i + 304}{-2 - 4i} = \frac{(-6 + 2i)^n}{5} - 1$$
5. **Add 1 to both sides:**
$$\frac{2a + 4i + 304}{-2 - 4i} + 1 = \frac{(-6 + 2i)^n}{5}$$
6. **Multiply both sides by 5:**
$$5\left( \frac{2a + 4i + 304}{-2 - 4i} + 1 \right) = (-6 + 2i)^n$$
7. **Simplify the left side:** Calculate the complex division and addition (requires knowing $a$) or treat $a$ as a constant.
8. **Express the right side in polar form:**
Find magnitude and argument of $-6 + 2i$:
$$| -6 + 2i | = \sqrt{(-6)^2 + 2^2} = \sqrt{36 + 4} = \sqrt{40} = 2\sqrt{10}$$
$$\theta = \arctan\left( \frac{2}{-6} \right) = \arctan(-\frac{1}{3}) = -0.32175 \text{ rad}$$
Since real part is negative and imaginary part is positive, the angle is in second quadrant:
$$\theta = \pi - 0.32175 = 2.81984 \text{ rad}$$
9. **Express $(-6 + 2i)^n$:**
$$(-6 + 2i)^n = (2\sqrt{10})^n \left( \cos(n \times 2.81984) + i \sin(n \times 2.81984) \right)$$
10. **Set this equal to the left side computed in step 6 and solve for $n$: (if desired, solve using logarithms on magnitude and arguments)**