1. **State the problem:**
Find the points of intersection A and B between the line $y=2$ and the parabola $y=\frac{1}{2}x^2$.
2. **Find points of intersection:**
Set the two equations equal to find $x$:
$$2 = \frac{1}{2}x^2$$
Multiply both sides by 2:
$$4 = x^2$$
Take the square root:
$$x = \pm 2$$
So the points are:
$$A = (2, 2), \quad B = (-2, 2)$$
3. **Find lengths of segments OA, OB, and AB:**
- $O = (0,0)$
- Length $OA = \sqrt{(2-0)^2 + (2-0)^2} = \sqrt{4 + 4} = \sqrt{8} = 2\sqrt{2}$
- Length $OB = \sqrt{(-2-0)^2 + (2-0)^2} = \sqrt{4 + 4} = 2\sqrt{2}$
- Length $AB = \sqrt{(2 - (-2))^2 + (2-2)^2} = \sqrt{4^2 + 0} = 4$
4. **Find area $S$ of triangle $OAB$:**
Use the formula for area of triangle with vertices $O(0,0)$, $A(2,2)$, $B(-2,2)$:
$$S = \frac{1}{2} \left| x_1(y_2 - y_3) + x_2(y_3 - y_1) + x_3(y_1 - y_2) \right|$$
Substitute:
$$S = \frac{1}{2} |0(2-2) + 2(2-0) + (-2)(0-2)| = \frac{1}{2} |0 + 4 + 4| = \frac{1}{2} \times 8 = 4$$
**Final answers:**
- Points of intersection: $A(2,2)$ and $B(-2,2)$
- Lengths: $OA = OB = 2\sqrt{2}$, $AB = 4$
- Area of triangle $OAB = 4$
Line Parabola Ae4509
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.