If you have studied algebra, you are probably familiar with grahping equations by using "x" and "y" values to plot points on a graph. (see illustration). This is known as the Cartesian coordinate method, named after its inventor, the French mathematician René Descartes (1596 - 1650). The horizontal x-axis (the abscissa) and the vertical y-axis (the ordinate) divide the graph into four quadrants.These four quadrants are always represented by Roman numerals and they are numbered, starting with the upper right quadrant going counterclockwise. So, if we were asked in which quadrant is the point (-2,-5) located, we'd say it is in Quadrant III because here, all x and y values are negative. That's about all you need to know about quadrants when studying algebra.
 In trigonometry, the above graphic is quite hepful in showing which of the 6 trigonometric functions are either positive or negative in each of the four quandrants. (If the function is printed in blue, it is positive in that quadrant and a red font indicates negative). Another graphic would be helpful in showing this.

"R E T U R N"