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).
Definition II: From the unit circle. Draw a unit circle, in that a circle of radius 1, centered at the origin of a 2-dimensional coordinate system. Given an angle q, the cos(q) can be defined as the x-coordinate of the point on the circle that is located at an angle q from the origin.