In X-Y Frame, A = xi +yj
In X'-Y' Frame, A' = x' i' +y'j'
If Angle of Rotation is K in Anti ClockWise Direction ( taken as + )
i' = i cos K + j sin K
j' =- i sin K + j cos K
or [ i' , j' ] =[ cos k sin K ] [ i ]
[ -sin K cos k ] [ j ]
or [i' , j' ] = R [i ]
[j ]
where R is rotation operator.
For Angle of Rotation K in ClockWise Direction ( taken as - )
[i' , j' ] = R' [ i]
[ j]
where R' =[ cosk -sink ] [ sink cosk ]
Similarly [x' , y' ] = R [ x ]
[ y ]
for (+) Angle of Rotation
and [x' , y' ] = R' [ x ] [ y ]
for (-) Angle of Rotation
( i , j ) --> ( i' , j' ) are called Base or Basis Vector transformation under Rotation.
sin ( -k ) = - sin k
cos( - k ) = cos k