If `vec a=vec p cosu+vec q sinu` where `vec p` and `vec q` are constant vectors.Prove that `vec a.[[d[vec a]]/[du] xx [d^2[vec a]]/[du^2]]=0`

If vec r=3vec p+4vec q and 2vec r=vec p-3vec q then

If vec P and vec Q are two vectors, then the value of (vec P + vec Q) xx (vec P - vec Q) is

If vec P xx vec Q= vec R, vec Q xx vec R= vec P and vec R xx vec P = vec Q then

If vec a=vec p+vec q,vec p xxvec b=0 and vec q*vec b=0 then prove that (vec b xx(vec a xxvec b))/(vec b*vec b)=vec q

For three vectors vec p,vec q and vec r if vec r=3vec p+4vec q and 2vec r=vec p-3vec q then

If vec p + vec q + vec r = xvec s and vec q + vec r + vec s = yvec p and are vec p, vec q, vec r non coplaner vectors then | vec p + vec q + vec r + vec r + vec s | =

If |vec p|=2|vec q|=3 then (|vec p xxvec q|)/(sin(vec p,vec q))=

If vec P+ vec Q = vec R and |vec P| = |vec Q| = | vec R| , then angle between vec P and vec Q is

vec P+vec Q+vec R=0 and vec |p|=8,vec |Q|=15 and vec |R|=17 angle between vec P and vec Q is