If x4+y4+z4=0, then ∣∣ ∣∣1xyyzzx1xyyzzx1∣∣ ∣∣= (where x,y,z∈R)
If sin−1x+sin−1y+sin−1z=π then x4+y4+z4+4x2y2z2=k(x2y2+y2z2+z2x2) where k is equal to