1. **State the problem:** Simplify the expression $$\frac{\sin \theta}{1+\cos \theta} + \frac{1+\cos \theta}{\sin \theta} = 2 \csc \theta$$ and verify the equality.
2. **Recall important identities:**
- $\csc \theta = \frac{1}{\sin \theta}$
- Use algebraic manipulation and trigonometric identities to simplify.
3. **Start with the left-hand side (LHS):**
$$\frac{\sin \theta}{1+\cos \theta} + \frac{1+\cos \theta}{\sin \theta}$$
4. **Find common denominator:**
$$\frac{\sin^2 \theta}{(1+\cos \theta) \sin \theta} + \frac{(1+\cos \theta)^2}{(1+\cos \theta) \sin \theta} = \frac{\sin^2 \theta + (1+\cos \theta)^2}{(1+\cos \theta) \sin \theta}$$
5. **Expand numerator:**
$$\sin^2 \theta + (1 + 2\cos \theta + \cos^2 \theta) = \sin^2 \theta + 1 + 2\cos \theta + \cos^2 \theta$$
6. **Use Pythagorean identity $\sin^2 \theta + \cos^2 \theta = 1$:**
$$1 + 1 + 2\cos \theta = 2 + 2\cos \theta = 2(1 + \cos \theta)$$
7. **Substitute back into fraction:**
$$\frac{2(1 + \cos \theta)}{(1+\cos \theta) \sin \theta}$$
8. **Cancel common factor $1 + \cos \theta$:**
$$\frac{\cancel{2(1 + \cos \theta)}}{\cancel{(1+\cos \theta)} \sin \theta} = \frac{2}{\sin \theta}$$
9. **Rewrite using cosecant:**
$$\frac{2}{\sin \theta} = 2 \csc \theta$$
10. **Conclusion:** The left-hand side simplifies exactly to the right-hand side, so the equality holds.
**Final answer:** $$\frac{\sin \theta}{1+\cos \theta} + \frac{1+\cos \theta}{\sin \theta} = 2 \csc \theta$$
Trig Expression 740Fec
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