1.4 Parametric EquationsGreg Kelly, Hanford High School, Richland, Washington
There are times when we need to describe motion (or a curve) that is not a function.We can do this by writing equations for the x and y coordinates in terms of a third variable (usually tor ).θ(29xft=(29yg t=These are calledparametric equations.“t” is the parameter. (It is also the independent variable)→
Example 1:0xtytt==≥To graph on the TI-89:MODEGraph…….2ENTERPARAMETRICY=(29xt1t=yt1t=2ndT)ENTERWINDOWGRAPH→
Hit zoom square to see the correct, undistorted curve.We can confirm this algebraically:xtyt==xy=2xy=0x≥2yx=0x≥parabolic function→