The transformation first scales the x-component by k and then rotates clockwise by θ degrees. Find the matrix for this transformation, according to the standard basis vectors.
a) [k, -sin(θ) ; 0, cos(θ) ]
b) [k, -sin(θ) ; sin(θ) , cos(θ) ]
c) [k, 0; 0, cos(θ) ]
d) [k, 0; sin(θ) , cos(θ) ]