1. **State the problem:** We need to evaluate the expression $$B = \frac{\sin\left(\frac{2\pi}{3}\right)}{\cos^2\left(-\frac{\pi}{3}\right)}$$ and simplify it.
2. **Recall important trigonometric values and rules:**
- $$\sin\left(\frac{2\pi}{3}\right) = \sin\left(\pi - \frac{\pi}{3}\right) = \sin\left(\frac{\pi}{3}\right) = \frac{\sqrt{3}}{2}$$
- $$\cos\left(-\frac{\pi}{3}\right) = \cos\left(\frac{\pi}{3}\right) = \frac{1}{2}$$ because cosine is an even function.
3. **Substitute these values into the expression:**
$$B = \frac{\frac{\sqrt{3}}{2}}{\left(\frac{1}{2}\right)^2}$$
4. **Simplify the denominator:**
$$\left(\frac{1}{2}\right)^2 = \frac{1}{4}$$
5. **Rewrite the expression:**
$$B = \frac{\frac{\sqrt{3}}{2}}{\frac{1}{4}}$$
6. **Divide by a fraction by multiplying by its reciprocal:**
$$B = \frac{\sqrt{3}}{2} \times \frac{4}{1}$$
7. **Multiply numerators and denominators:**
$$B = \frac{\sqrt{3} \times 4}{2} = \frac{4\sqrt{3}}{2}$$
8. **Simplify the fraction by canceling common factors:**
$$B = \frac{\cancel{4}\sqrt{3}}{\cancel{2}} \times 2 = 2\sqrt{3}$$
**Final answer:**
$$B = 2\sqrt{3}$$
Trig Expression 8E55E1
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