Bayangan titik (4,-5) oleh R (p,90°) adalah (10,5) koordinat pusat rotasi adalah

jawab
A(x,y) = (4, - 5)
R(p, 90) →P(a,b), α =90
A' (x', y') = (10, 5)

[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}x - a\\y-b\end{array}\right] \\ [/tex]

(i)
x' - a = -1(y - b)
10 - a =  -(-5 -b)
10- a = 5 + b
-a - b = - 5 ...(i)

(ii)
5-b = 4 - a
a - b = - 1 ...(ii)

(i) dan (ii)
- a - b = - 5
a - b = - 1 ||(+)
-2b = - 6
b = 3

a - b = -1
a - 3 = -1
a = 2
P(a,b) = (2, 3)