Cosine Angles 8Dc56D
1. **State the problem:** Solve the equation $2\cos^2 x = 1$ for $0 < x < 360$ degrees.
2. **Rewrite the equation:** Divide both sides by 2 to isolate $\cos^2 x$:
$$\cos^2 x = \frac{1}{2}$$
3. **Take the square root:** Recall that $\cos^2 x = (\cos x)^2$, so
$$\cos x = \pm \sqrt{\frac{1}{2}} = \pm \frac{\sqrt{2}}{2}$$
4. **Find angles where $\cos x = \frac{\sqrt{2}}{2}$:**
This occurs at
$$x = 45^\circ, 315^\circ$$
5. **Find angles where $\cos x = -\frac{\sqrt{2}}{2}$:**
This occurs at
$$x = 135^\circ, 225^\circ$$
6. **Final answer:** The solutions in the interval $0 < x < 360$ are
$$x = 45^\circ, 135^\circ, 225^\circ, 315^\circ$$