Circle Standard Form
1. The problem asks for the equation of a circle with center at the origin and radius $s$.
2. The general equation for a circle with center at the origin $(0,0)$ and radius $r$ is:
$$x^2 + y^2 = r^2$$
3. Substituting the radius $s$ into the equation, we get:
$$x^2 + y^2 = s^2$$
This is the equation of the circle.
4. Next, we need to reduce the equation $2x^2 - x + 4y = 3$ to standard form.
5. Start with the given equation:
$$2x^2 - x + 4y = 3$$
6. Isolate the $y$ term:
$$4y = 3 - 2x^2 + x$$
7. Divide both sides by 4:
$$y = \frac{3}{4} - \frac{2}{4}x^2 + \frac{1}{4}x = \frac{3}{4} - \frac{1}{2}x^2 + \frac{1}{4}x$$
8. Rearrange the terms:
$$y = -\frac{1}{2}x^2 + \frac{1}{4}x + \frac{3}{4}$$
9. This is a quadratic in $x$ with $y$ expressed as a function of $x$, representing a parabola.
10. To write in standard form, complete the square for the $x$ terms.
11. Factor out $-\frac{1}{2}$ from the $x^2$ and $x$ terms:
$$y = -\frac{1}{2}\left(x^2 - \frac{1}{2}x\right) + \frac{3}{4}$$
12. Complete the square inside the parentheses:
Take half of $-\frac{1}{2}$ which is $-\frac{1}{4}$, square it gives $\left(-\frac{1}{4}\right)^2 = \frac{1}{16}$.
Add and subtract $\frac{1}{16}$ inside the parentheses:
$$y = -\frac{1}{2}\left( x^2 - \frac{1}{2}x + \frac{1}{16} - \frac{1}{16} \right) + \frac{3}{4}$$
13. Group to form a perfect square and simplify:
$$y = -\frac{1}{2}\left( x - \frac{1}{4} \right)^2 + \frac{1}{32} + \frac{3}{4}$$
14. Combine constants:
$$\frac{1}{32} + \frac{3}{4} = \frac{1}{32} + \frac{24}{32} = \frac{25}{32}$$
15. Final standard form:
$$y = -\frac{1}{2}\left( x - \frac{1}{4} \right)^2 + \frac{25}{32}$$
This is the standard form of the parabola.