Escitalopram is an oral drug that is used for treating depression and generalized anxiety disorder. Chemically, escitalopram is similar to citalopram . Both are in a class of drugs called selective serotonin reuptake inhibitors (SSRIs), a class that also includes fluoxetine , paroxetine and sertraline .
1 A circle is all of the points that are a fixed distance, known as the radius, from a given point, known as the center of the circle. 2  Explore the standard equation of a circle using the applet below (Go here for a larger version).
Circle Equations. A circle is easy to make: Draw a curve that is radius away from a central point. And so: All points are the same distance. from the center. In fact the definition of a circle is. Circle: The set of all points on a plane that are a fixed distance from a center. Let us put that center at (a,b) . So the circle is all the points (x,y) that are r away from the center (a,b) .