1. **State the problem:** Solve the inequality $$\sin^2 x - \sin x \geq 1$$ for real values of $x$.
2. **Rewrite the inequality:** Let $y = \sin x$. The inequality becomes:
$$y^2 - y \geq 1$$
3. **Bring all terms to one side:**
$$y^2 - y - 1 \geq 0$$
4. **Solve the quadratic inequality:**
The quadratic expression is $$y^2 - y - 1$$.
5. **Find roots of the quadratic equation:**
$$y^2 - y - 1 = 0$$
Using the quadratic formula:
$$y = \frac{1 \pm \sqrt{1^2 - 4 \cdot 1 \cdot (-1)}}{2 \cdot 1} = \frac{1 \pm \sqrt{1 + 4}}{2} = \frac{1 \pm \sqrt{5}}{2}$$
6. **Calculate roots:**
$$y_1 = \frac{1 - \sqrt{5}}{2} \approx -0.618$$
$$y_2 = \frac{1 + \sqrt{5}}{2} \approx 1.618$$
7. **Analyze the inequality:**
Since the leading coefficient of $y^2$ is positive, the parabola opens upwards.
The inequality $$y^2 - y - 1 \geq 0$$ holds when:
$$y \leq y_1 \quad \text{or} \quad y \geq y_2$$
8. **Consider the domain of $\sin x$:**
Since $\sin x$ ranges between $-1$ and $1$, the interval $$y \geq y_2 \approx 1.618$$ is impossible.
Therefore, the solution reduces to:
$$\sin x \leq \frac{1 - \sqrt{5}}{2} \approx -0.618$$
9. **Find $x$ values satisfying $\sin x \leq -0.618$:**
The sine function is periodic with period $2\pi$.
The solutions are all $x$ such that:
$$\sin x \leq -0.618$$
This corresponds to the arcsin values:
$$x \in [\arcsin(-1), \arcsin(-0.618)] \cup [\pi - \arcsin(-0.618), \pi - \arcsin(-1)]$$
Since $\arcsin(-1) = -\frac{\pi}{2}$ and $\arcsin(-0.618) \approx -0.666$ radians,
The intervals where $\sin x \leq -0.618$ are:
$$x \in \left[-\frac{\pi}{2} + 2k\pi, -0.666 + 2k\pi\right] \cup \left[\pi + 0.666 + 2k\pi, \frac{3\pi}{2} + 2k\pi\right]$$
for all integers $k$.
**Final answer:**
$$\boxed{\sin x \leq \frac{1 - \sqrt{5}}{2}}$$
which corresponds to the intervals above for $x$.
Sin Inequality B6C5E9
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.