1. **State the problem:** Solve the equation $$6 \cos^2 \theta - 4 = \sin \theta$$ for $$0^\circ \leq \theta \leq 360^\circ$$.
2. **Use the Pythagorean identity:** Recall that $$\cos^2 \theta = 1 - \sin^2 \theta$$.
3. **Substitute into the equation:**
$$6(1 - \sin^2 \theta) - 4 = \sin \theta$$
4. **Simplify:**
$$6 - 6 \sin^2 \theta - 4 = \sin \theta$$
$$2 - 6 \sin^2 \theta = \sin \theta$$
5. **Rearrange to form a quadratic in $$\sin \theta$$:**
$$-6 \sin^2 \theta - \sin \theta + 2 = 0$$
6. **Multiply both sides by $$-1$$ to simplify:**
$$\cancel{-6} \sin^2 \theta + \cancel{-} \sin \theta - \cancel{2} = 0 \Rightarrow 6 \sin^2 \theta + \sin \theta - 2 = 0$$
7. **Solve the quadratic equation:**
Use the quadratic formula $$\sin \theta = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$$ where $$a=6$$, $$b=1$$, $$c=-2$$.
Calculate the discriminant:
$$\Delta = 1^2 - 4 \times 6 \times (-2) = 1 + 48 = 49$$
Calculate roots:
$$\sin \theta = \frac{-1 \pm \sqrt{49}}{2 \times 6} = \frac{-1 \pm 7}{12}$$
8. **Find the two possible values:**
- $$\sin \theta = \frac{-1 + 7}{12} = \frac{6}{12} = 0.5$$
- $$\sin \theta = \frac{-1 - 7}{12} = \frac{-8}{12} = -\frac{2}{3} \approx -0.6667$$
9. **Find $$\theta$$ for each value in the interval $$0^\circ \leq \theta \leq 360^\circ$$:**
- For $$\sin \theta = 0.5$$, $$\theta = 30^\circ$$ or $$150^\circ$$.
- For $$\sin \theta = -\frac{2}{3}$$, $$\theta = 360^\circ - \arcsin\left(\frac{2}{3}\right) \approx 360^\circ - 41.81^\circ = 318.19^\circ$$ and $$\theta = 180^\circ + 41.81^\circ = 221.81^\circ$$.
10. **Final solutions:**
$$\theta = 30^\circ, 150^\circ, 221.81^\circ, 318.19^\circ$$
Trig Equation 3961Bc
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