Two adjacent sides of a parallelogram ABCD are given by `vec(AB)=2hati+10hatj+11hatk` and `vec(AD)=-hati+2hatj+2hatk`. The side AD is rotated by an acute angle `alpha` in the plane of the parallelogram so that AD becomes AD'. If AD' make a right angle withe the side AB then the cosine of the angle `alpha` is given by

Two adjacent sides of a parallelogram ABCD are given by : vec(AB) = 2hati + 10 hatj+ 11 hatk and vec(AD) =- hati + 2 hatj + 2 hatk. The side AD is rotated by an acute angle alpha in the plane of the parallelogram so that AD becomes AD'. If AD' makes a right angle with the side AB, then the cosine of the angle alpha is given by

Two adjacent sides of a parallelogram A B C D are given by vec A B=2 hat i+10 hat j+11 hat ka n d vec A D=- hat i+2 hat j+2 hat kdot The side A D is rotated by an acute angle alpha in the plane of the parallelogram so that A D becomes A D^(prime)dot If A D ' makes a right angle with the side A B , then the cosine of the angel alpha is given by

The adjacent sides of a parallelogram are given by vecA=hati+hatj-4hatk and vecB=2hati-hatj+4hatk . Calculate the area of parallelogram.

In a parallelogram ABCD, vec(AB)=hati+hatj+hatk and diagonal vec(AC)=hati-hatj+hatk then angleBAC = …………….

Two adjacent sides of a parallelogram ABCD are 2hati+4hatj -5 hatkand hati+2hatj+3hatk . Then the value of |vec(AC)xxvec(BD)| is