jika titik p (2-3) dirotasikan sebesar 90 searah arah jarum jam dengan pusat 0(0,0), bayangan titik P adalah

Penyelesaian:

Dik: titik p = (2,-3)
dirotasikan sebesar 90° pusat (0,0)

p'...?

Jawab:

[tex]\left[\begin{array}{c}x'\\y'\end{array}\right] = \left[\begin{array}{cc}cos \alpha &-sin \alpha \\sin \alpha &cos \alpha \end{array}\right] \left[\begin{array}{c}2\\-3\end{array}\right] [/tex]

[tex]\left[\begin{array}{c}x'\\y'\end{array}\right] = \left[\begin{array}{cc}0&-1\\1&0\end{array}\right] \left[\begin{array}{c}2\\-3\end{array}\right] [/tex]

didapat = x' = 3
y' = 2

Maka p' = (3,2)