If you are given an equation of ellipse in the form of a function whose value is a square root, you may need to simplify it to make it look like the equation of an ellipse. Now equate the function to a variable y and perform squaring on both sides to remove the radical. Now simplify the equation and get it in the form of (x*x)/(a*a) + (y*y)/(b*b) = 1 which is the general form of an ellipse. Now you will have the x and y intercepts which are a and b respectively. Using this values graph the equation of the ellipse. But initially you were given with a function whose value was under root of something. So as its value cant be negative you have to strike that part of the ellipse which is negative giving you the half ellipse. This video shows how to graph half an ellipse.