tentukan bayangan titik q (-2,1) jika diputar dengan pusat titik a (1,-3) dengan sudut putar 90 derajat

jawab

Q(x, y)= (-2,1)
P(a,b) = (1, 3)
T(90°)= |0 ..-1||1...0|

[tex] \left[\begin{array}{ccc}x' -a\\y'- b\end{array}\right] \,= \left[\begin{array}{ccc}0&-1\\1&0\end{array}\right] \, \left[\begin{array}{ccc}-2 - a\\1-b\end{array}\right] \\ \left[\begin{array}{ccc}x' -1\\y'- 3\end{array}\right] \,= \left[\begin{array}{ccc}0&-1\\1&0\end{array}\right] \, \left[\begin{array}{ccc}-3\\-2\end{array}\right] \\ x' -1 = 2 , x' = 3 y' - 3 = -3 , y' = 0 \\ bayangan\, Q(-2, 1) \, = Q'(3, 0) [/tex]