Question

How do you write an equation of a line with center at the origin and `r=sqrt7`?

Answer 1

`x^2+y^2=7`

Explanation:

I am assuming you require the equation of a circle since the question gives centre and radius.

The standard form of the `color(blue)"equation of a circle"` is.

`color(red)(bar(ul(|color(white)(2/2)color(black)((x-a)^2+(y-b)^2=r^2)color(white)(2/2)|)))`
where (a ,b) are the coordinates of the centre and r, the radius.

`"here the centre "=(0,0)" and "r=sqrt7`

`rArr(x-0)^2+(y-0)^2=(sqrt7)^2`

simplifying gives.

`x^2+y^2=7larrcolor(red)" equation of circle"`