If `u = a + b , v = a - b ,|a| = |b| = 2` then `| u xx v |=`

vec u = vec a-vec b, vec v = vec a + vec b and | vec a | = | vec b | = 2 then | vec u xxvec v | is equal to

If 5u + 3v = 13uv and u -v = uv , then (u, v) = _____

If bar(u)=bar(a)+bar(b),bar(v)=bar(a)-bar(b),|bar(a)|=|bar(b)|=2 then |bar(u)xxbar(v)|=

Let vec a and vec b be two non-collinear unit vector.If vec u=vec a-(vec a*vec b)vec b and vec v=vec a xxvec b, then |vec v| is |vec u| b.|vec u|+|vec u*vec a|c.|vec u|+|vec u*vec b|d|vec u|+widehat u.|vec a+vec b|