The restrictions are still the same: you can have one and only one instance of the dependent variable r, although it can be located almost anywhere in the equation. The only difference in what you type, and the way Graphmatica detects a polar graph, is that you must use the variables t and r instead of x and y. Polar graphs can be typed in the equation combobox just like normal graphs. The domain for the graphing is 0 to 2pi (the first complete circle in the positive direction), but you can easily change these values using the Theta Range function in the Options menu. To make a graph using polar coordinates, we let theta be the independent variable and calculate a distance to plot out from the origin as we let the angle sweep around in the positive direction. To put a polar coordinate into Cartesian terms in order to graph it, we use the equations: x = r cos t and y = r sin t. There are 2pi radians in a complete circle, corresponding to 360 of the degrees you're familiar with. The direction is measured in radians as an angle starting from the positive side of the x-axis and turning around counter-clockwise (like measuring the angle the hand on a clock has traveled starting at the 3 o'clock position and going backwards). The t tells what direction to go in from the origin, and the r tells how far to go out in that direction to reach the point. The traditional Cartesian method relies on an x and a y coordinate to mark how far a point is from the axes in two perpendicular directions polar coordinates plot the location of a point by one coordinate represented by the Greek letter theta which is simplified to t in Graphmatica and another called r. The concept is pretty easy to grasp graphically, but if you have never used polar coordinates and want to understand them, you should probably read the section below. See (Figure), (Figure), and (Figure).Polar coordinates are a fundamentally different approach to representing curves in two-dimensional space. Using the appropriate substitutions makes it possible to rewrite a polar equation as a rectangular equation, and then graph it in the rectangular plane.Transforming equations between polar and rectangular forms means making the appropriate substitutions based on the available formulas, together with algebraic manipulations.To convert from rectangular coordinates to polar coordinates, use one or more of the formulas: and See (Figure).To convert from polar coordinates to rectangular coordinates, use the formulas and See (Figure) and (Figure).If is negative, extend the directed line segment in the opposite direction of See (Figure).To plot a point in the form move in a counterclockwise direction from the polar axis by an angle of and then extend a directed line segment from the pole the length of in the direction of If is negative, move in a clockwise direction, and extend a directed line segment the length of in the direction of See (Figure).The polar grid is represented as a series of concentric circles radiating out from the pole, or origin.This point is plotted on the grid in (Figure). For example, to plot the point we would move units in the counterclockwise direction and then a length of 2 from the pole. The angle measured in radians, indicates the direction of We move counterclockwise from the polar axis by an angle of and measure a directed line segment the length of in the direction of Even though we measure first and then the polar point is written with the r-coordinate first. The first coordinate is the radius or length of the directed line segment from the pole. The polar grid is scaled as the unit circle with the positive x-axis now viewed as the polar axis and the origin as the pole. The polar grid is represented as a series of concentric circles radiating out from the pole, or the origin of the coordinate plane.
In this section, we introduce to polar coordinates, which are points labeled and plotted on a polar grid.
However, there are other ways of writing a coordinate pair and other types of grid systems. When we think about plotting points in the plane, we usually think of rectangular coordinates in the Cartesian coordinate plane.