Question 156855
You graph "circles" by plotting two graphs as follows:
First, solve the given equation for y:
{{{x^2+4y^2 = 1}}} Subtract x^2 from both sides.
{{{4y^2 = -x^2+1}}} Now divide both sides by 4.
{{{y^2 = (-x^2+1)/4}}} Finally, take the square root of both sides.
{{{y = sqrt((-x^2+1)/2)}}} or {{{y = -sqrt((-x^2+1)/2)}}}
Now when you graph these two functions, you'll see half the "circle" above the x-axis and the other half "circle" below the x-axis.
{{{graph(400,400,-3,3,-3,3,sqrt((-x^2+1)/2),-sqrt((-x^2+1)/2))}}}