Let f(α)=⎡⎢⎣cosα−sinα0sinαcosα0001⎤⎥⎦, then (f(α))−1 is equal to
If α,β are the roots of the equation ax2+bx+c=0, then the value of determinant ∣∣ ∣ ∣∣1cos(α−β)cosαcos(α−β)1cosβcosαcosβ1∣∣ ∣ ∣∣ is equal to