If `veca xx vecb = vecc xx vecd` and `veca xx vecc = vecb xx vecd`, then show that `veca - vecd` is parallel to `vecb - vecc`, where `a != d` and `b != c`

If vecaxxvecb=veccxxvecd and vecaxxvecc=vecbxxvecd show that (veca-vecd) is parallel to (vecb-vecc) . It is given that veca!=vecd and vecb!=vecc .

If (veca xx vecb) xx (vecc xx vecd) . (veca xx vecd) =0 then which of the following may be true ?

If (veca xx vecb) xx (vecc xx vecd) . (veca xx vecd) =0 then which of the following may be true ?

If (veca xxv vecb) xx (vecc xx vecd) . (veca xx vecd) =0 then which of the following may be true ?

If veca, vecb, vecc and vecd ar distinct vectors such that veca xx vecc = vecb xx vecd and veca xx vecb = vecc xx vecd . Prove that (veca-vecd).(vecc-vecb)ne 0, i.e., veca.vecb + vecd.vecc nevecd.vecb + veca.vecc.

If veca, vecb, vecc and vecd ar distinct vectors such that veca xx vecc = vecb xx vecd and veca xx vecb = vecc xx vecd . Prove that (veca-vecd).(vecc-vecb)ne 0, i.e., veca.vecb + vecd.vecc nevecd.vecb + veca.vecc.

If veca, vecb,vecc and vecd are distinct vectors such that veca xx vecc = vecb xx vecd and veca xx vecb = vecc xx vecd . Prove that (veca-vecd).(vecc-vecb)ne 0, i.e., veca.vecb + vecd.vecc nevecd.vecb + veca.vecc.

Given vecC = vecA xx vecB and vecD = vecB xx vecA . What is the angle between vecC and vecD ?

Given vecC = vecA xx vecB and vecD = vecB xx vecA . What is the angle between vecC and vecD ?

Show that (veca xx vecb) *(vecc xx vecd) +(vecb xx vecc) *(veca xx vecd) +(vecc xx veca) *(vecb xx vecd)=0 .