Solve Tan Sin B44271
1. **State the problem:** Solve the equation $$4 \tan \theta + 5 \sin \theta = 0$$ for $$0 < \theta \leq 360^\circ$$.
2. **Recall the definitions and formulas:**
- $$\tan \theta = \frac{\sin \theta}{\cos \theta}$$.
- The equation can be rewritten using this identity.
3. **Rewrite the equation:**
$$4 \tan \theta + 5 \sin \theta = 0 \implies 4 \frac{\sin \theta}{\cos \theta} + 5 \sin \theta = 0$$
4. **Factor out $$\sin \theta$$:**
$$\sin \theta \left( \frac{4}{\cos \theta} + 5 \right) = 0$$
5. **Set each factor equal to zero:**
- $$\sin \theta = 0$$
- $$\frac{4}{\cos \theta} + 5 = 0$$
6. **Solve $$\sin \theta = 0$$ for $$0 < \theta \leq 360^\circ$$:**
- $$\sin \theta = 0$$ at $$\theta = 0^\circ, 180^\circ, 360^\circ$$.
- Since $$0 < \theta \leq 360^\circ$$, valid solution is $$\theta = 180^\circ$$.
7. **Solve $$\frac{4}{\cos \theta} + 5 = 0$$:**
- Multiply both sides by $$\cos \theta$$ (note $$\cos \theta \neq 0$$):
$$4 + 5 \cos \theta = 0$$
- Rearrange:
$$5 \cos \theta = -4$$
- Divide:
$$\cos \theta = -\frac{4}{5} = -0.8$$
8. **Find $$\theta$$ where $$\cos \theta = -0.8$$ in $$0 < \theta \leq 360^\circ$$:**
- $$\cos \theta = -0.8$$ occurs in the second and third quadrants.
- Use inverse cosine:
$$\theta = \cos^{-1}(-0.8)$$
- Calculate:
$$\theta_1 = 143.1^\circ$$ (second quadrant)
$$\theta_2 = 216.9^\circ$$ (third quadrant)
9. **List all solutions:**
$$\theta = 180^\circ, 143.1^\circ, 216.9^\circ$$
**Final answer:** $$\boxed{\theta = 143.1^\circ, 180^\circ, 216.9^\circ}$$