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).
2.4 Circles. A circle with center at C and the radius r is the set of all points (x, y) whose distance from C is r. The equation of a circle with center at C(h,k) and radius r is therefore: (x-h)2 + (y-k)2 = r2. This equation is called the standard equation of the circle.