Question 698798
{{{f(x) = sqrt(c-x^2)}}} ....if the point is at [{{{-13}}},{{{13}}}], means {{{x=-13}}} and {{{f(x)=13}}}; so, we will plug it in formula

{{{f(x) = sqrt(c-x^2)}}} and solve for {{{c}}}

{{{13 = sqrt(c-(-13)^2)}}}

{{{13 = sqrt(c-169)}}}...both sides raise to power of two

{{{13^2 = (sqrt(c-169))^2}}}

{{{169 = c-169}}}

{{{169+169 = c}}}

{{{338= c}}}

so, you have a function {{{f(x) = sqrt(338-x^2)}}} that has a solution set {{{x=-13}}} and {{{f(x)=13}}}

let's see it on a graph:


{{{ graph( 600, 600, -15, 15, -15, 15, sqrt(338-x^2)-13) }}}