Let the vector `veca, vecb, vecc, vecd` be such that `(veca xx vecb) xx (vecc xx vecd) = vec0`. Let `P_1`, and `P_2`, be planes determined by the vectors `veca, vecb` and `vecc, vecd` respectively. Then the angle between `P_1`, and `P_2`, is

Let the vectors veca, vecb,vecc and vecd be such that (vecaxxvecb)xx(veccxxvecd)=vec0 . Let P_1 and P_2 be planes determined by pairs of vectors veca,vecb and vecc,vecd respectively. Then the angle between P_1 and P_2 is (A) 0 (B) pi/4 (C) pi/3 (D) pi/2

Let the vectors veca, vecb,vecc and vecd be such that (vecaxxvecb)xx(veccxxvecd)=vec0 . Let P_1 and P_2 be planes determined by pairs of vectors veca,vecb and vecc,vecd respectively. Then the angle between P_1 and P_2 is (A) 0 (B) pi/4 (C) pi/3 (D) pi/2

If veca, vecb, vecc, vecd are coplanar vectors, then (vecaxxvecb)xx(veccxxvecd)=

If veca,vecb,vecc,vecd are coplaner vectors, then (vecaxxvecb)xx(veccxxvecd)=

If veca , vecb, vecc and vecd are unit vectors such that (veca xx vecb). (veccxx vecd) =1 and veca. Vecc= 1/2 then :

for any four vectors veca,vecb, vecc and vecd prove that vecd. (vecaxx(vecbxx(veccxxvecd)))=(vecb.vecd)[veca vecc vecd]

for any four vectors veca,vecb, vecc and vecd prove that vecd. (vecaxx(vecbxx(veccxxvecd)))=(vecb.vecd)[veca vecc vecd]

for any four vectors veca,vecb, vecc and vecd prove that vecd. (vecaxx(vecbxx(veccxxvecd)))=(vecb.vecd)[veca vecc vecd]