Given that `0.4hati+0.8hatj+b hatk` is a unit vector . What is the value of b ?

The vector veca=1/4(2hati-2hatj+hatk) (A) is a unit vector (B) makes an angle of pi/3 with the vector (hati+1/2 hatj-hatk) (C) is parallel to the vector 7/4hati-7/4hatj+7/8hatk (D) none of these

The vector veca=1/4(2hati-2hatj+hatk) (A) is a unit vector (B) makes an angle of pi/3 with the vector (hati+1/2 hatj-hatk) (C) is parallel to the vector 7/4hati-7/4hatj+7/8hatk (D) none of these

The scalar product of the vector hati+hatj+hatk with a unit vector along the sum of vectors 2 hati+4 hatj-5 hatk and lambda hati+2 hatj+3 hatk is equal to one. Find the value of lambda

The scalar product of the vector hati+hatj+hatk with a unit vector along the sum of the vectors 2hati+4hatj-5hatk and lamda hati+2hatj+3hatk is equal to one. Find the value of lamda .

The scalar product of the vector hati+hatj+hatk with a unit vector along the sum of vectors 2hati+4hatj-5hatk and lambda hati+2hatj+3hatk is equal to one. Find the value of lambda .

The scalar product of the vector hati+3hatj+3hatk with a unit vector along the sum of vectors hati-3hatj+4hatk and lambdahati-4hatj+5hatk is equal to one. Find the value of lambda .