Integral Arcsin
1. **State the problem:** Evaluate the definite integral $$\int_0^1 \frac{1}{\sqrt{4 - x^2}} \, dx$$.
2. **Recall the formula:** The integral $$\int \frac{1}{\sqrt{a^2 - x^2}} \, dx = \arcsin\left(\frac{x}{a}\right) + C$$ where $a > 0$.
3. **Identify parameters:** Here, $a = 2$ since $4 = 2^2$.
4. **Apply the formula:**
$$\int \frac{1}{\sqrt{4 - x^2}} \, dx = \arcsin\left(\frac{x}{2}\right) + C$$
5. **Evaluate the definite integral:**
$$\int_0^1 \frac{1}{\sqrt{4 - x^2}} \, dx = \left[ \arcsin\left(\frac{x}{2}\right) \right]_0^1 = \arcsin\left(\frac{1}{2}\right) - \arcsin(0)$$
6. **Calculate values:**
- $\arcsin\left(\frac{1}{2}\right) = \frac{\pi}{6}$ (since $\sin(\pi/6) = 1/2$)
- $\arcsin(0) = 0$
7. **Final answer:**
$$\int_0^1 \frac{1}{\sqrt{4 - x^2}} \, dx = \frac{\pi}{6}$$
This means the area under the curve from $x=0$ to $x=1$ is $\frac{\pi}{6}$.