HP 40gs HP 39gs_40gs_Mastering The Graphing Calculator_English_E_F2224-90010.p - Page 311

I want to graph this function for the first six seconds but I am not sure what y scale to use so I will set XRng to be 0 to 6 in the PLOT SETUP view and then choose VIEWS - Auto Scale. The result is shown right. Using Extremum, I find that the time of closest approach is at t = 3.4 hours (3:24 pm) with a separation at that time of d = 1.3416 km. The y axis has been adjusted slightly to make the x axis visible. Circular Motion and the Dot Product A particle's position at time t seconds is given by r = 5sinθ i − 5cosθ j . Draw a sketch of its path for the first 6 seconds of movement. Show that its path is circular. The first step is to graph the particle's path. We go into the Parametric aplet and enter the rule into the first equation X1, Y1. After setting TRng to 0 to 6 and then using VIEWS - Auto Scale we get a result which is does not look like a circle, but this may be due to distortion through not using a 'square' screen. If we inspect the PLOT SETUP view, we can see that the settings are nearly double those of the default 'square' screen of -6.5 to 6.5 and 3.1 to 3.2 In the PLOT SETUP view, press SHIFT CLEAR to set everything back to default, then double each setting for the x and y axes and set TRng back to 0 to 6. Pressing PLOT again will make it clear visually that this is a circle and we can copy this diagram onto our test paper as the required graph. Note the gap at the bottom because the TRng stops at 6 instead of 2π. Of course, this is not really a proof of circularity! 311