Operation Manual
Chapter 17: Activities 315
4. Press y / 5 to select 5:Intersect. The graph is displayed. Select a first curve, second curve, and
guess for the intersection toward the left side of the display. The solution is displayed, and the
value of
X at the intersection, which is the lower limit of the integral, is stored in Ans and X.
5. Press y 5 to go to the home screen. Press y< 7 and use Shade( to see the area
graphically.
Shade(Y2,Y1,Ans,75, 4, 4, 18)
6. Press y 5 to return to the home screen. Enter the expression to evaluate the integral for the
shaded region.
fnInt(Y1NY2,X,Ans,75)
The area is 325.839962.
Using Parametric Equations: Ferris Wheel Problem
Problem
Using two pairs of parametric equations, determine when two objects in motion are closest to each
other in the same plane.
A ferris wheel has a diameter (d) of 20 meters and is rotating counterclockwise at a rate (s) of one
revolution every 12 seconds. The parametric equations below describe the location of a ferris wheel
passenger at time T, where a is the angle of rotation, (0,0) is the bottom center of the ferris wheel, and
(10,10) is the passenger’s location at the rightmost point, when T=0.
X(T) = r cos a
Y(T) = r + r sin a
where a = 2pTs and r = dà 2