`vec a` and `vec b` are unit vectors and `vec a+2vec b` is perpendicular to `5vec a-4vec b` ,then `2(vec a.vec b)` is equal to

(vec a.vec b)vec c

If vec a and vec b are non-collinear unit vectors and |vec a+vec b|=sqrt(3) then (2vec a+5vec b)*(3vec a-vec b)=

If vec a and vec b are unit vectors such that |vec a xxvec b|=vec a.vec b then |vec a-vec b|^(2) is equal to

Let vec a and vec b be two unit vectors such that |vec a+vec b|=sqrt(3) if vec c=vec a+2vec b+3(vec aXvec b) then 2|vec c| is equal to

If vec(a).vec(b) and vec(c ) are unit vectors such that vec(a) is perpendicular to the plane of vec(b) , vec(c ) and the angle between vec(b) and vec(c ) is (pi)/(3) . Then what is |vec(a) +vec(b)+vec(c )| ?

If vec a, vec b and vec c are unit vectors then | vec a-vec b | ^ (2) + | vec b-vec c | ^ (2) + | vec c-vec a | ^ (2) is equal to

If vec a and vec b are two unit vectors and the angle between them is 60^@ then ((1+vec a.vec b))/((1-vec a.vec b)) is

Let vec a,vec b and vec c are vectors of magnitude 3,4,5 respectively.If vec a is perpendicular to vec b+vec c,vec b is perpendicular to vec c+vec a and vec c is perpendicular to vec a+vec b then find the magnitude of vec a+vec b+vec c

If vec a and vec b are orthogonal unit vectors, then for a vector vec r noncoplanar with vec a and vec b , vector rxxa is equal to a. [ vec r vec a vec b] vec b-( vec r. vec b)( vec bxx vec a) b. [ vec r vec a vec b]( vec a+ vec b) c. [ vec r vec a vec b] vec a-( vec r. vec a) vec axx vec b d. none of these

Let vec a,vec b, and vec c are vectors such that |vec a|=3,|vec b|=4 and |vec c|=5, and (vec a+vec b) is perpendicular to vec c,(vec b+vec c) is perpendicular to vec a and (vec c+vec a) is perpendicular to vec b. Then find the value of |vec a+vec b+vec c|