Let F(α)=⎡⎢⎣cosα−sinα0sinαcosα0001⎤⎥⎦, where αϵR. Then [F(α)]−1 is equal to
If A=[cos2αcosα sinαcosα sinαsin2α] and B=[cos2βcosβ sinβcosβ sinβsin2β] are two matrices such that AB is the null matrix, then