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).
where (x 0, y 0) is the center of the circle and R its radius. The polar coordinates of a circle centered at the origin are particularly simple: r = R. A segment of a line joining two points on a circle is called a chord; a piece of a circle between two points is an arc.