Let the coordinates of the points be P(3cosα,2sinα), Q(xQ,yQ), and R(xR,yR).
The centroid of △PQR is given by:
(33cosα+xQ+xR,32sinα+yQ+yR)
We are given that the centroid is (2+cosα,3+32sinα). Equating the coordinates, we get:
33cosα+xQ+xR=2+cosα⟹xQ+xR=6
32sinα+yQ+yR=3+32sinα⟹yQ+yR=9
Since the point R lies on the line x+y=5, we have xR=5−yR.
Substituting xR into the equation for xQ:
xQ=6−xR=6−(5−yR)=yR+1
And we already have yQ=9−yR.
The point Q(xQ,yQ) lies on the circle x2+y2−14x−14y+82=0. Rewriting the circle's equation in standard form:
(x−7)2+(y−7)2=16
Substitute xQ and yQ into the circle's equation:
(yR+1−7)2+(9−yR−7)2=16
(yR−6)2+(2−yR)2=16
Expanding the terms:
y_R^2 - 12y_R + 36 + y_R^2 - 4y_R + 4 = 16
2y_R^2 - 16y_R + 40 = 16
2y_R^2 - 16y_R + 24 = 0
y_R^2 - 8y_R + 12 = 0
Factoring the quadratic equation:
(yR−2)(yR−6)=0
Thus, the possible ordinates for point R are yR=2 and yR=6.
The sum of the ordinates of all possible points R is 2+6=8.
Answer: 8