If `theta` is th angle between the unit vectors a and b , then prove that `cos(theta/2)=1/2| vec a+ vec b|`,and `sin(theta/2)=1/2| vec a- vec b|`

If theta is the angle between two vectors vec(a) and vec(b) , then vec(a).vec(b) ge 0 only when

If theta is the angle between two vectors vec(a) and vec(b) , then vec(a).vec(b) ge 0 only when

If vector vec a+ vec b bisects the angle between vec a and vec b , then prove that | vec a| = | vec b| .

If vec a+ vec b+ vec c= vec0, show that the angle theta between the vectors vec b\ a n d\ vec c ig givne by costheta=(| vec a|^2-| vec b|^2-| vec c|^2)/(2| vec b|| vec c|)dot

If vec a+ vec b+ vec c= vec0 , show that the angle theta between the vectors vec b and vec c is given by costheta=(| vec a|^2-|b|^2-| vec c|^2)/(2| vec b|| vec c|)

If theta is the angle between any two vectors vec a and vec b , then vec a. vec b=| vec axx vec b| when theta is equal to (a) 0 (B) pi/4 (C) pi/2 (d) pi

Find the angle between two vectors vec a and vec b , if | vec a xx vec b|= vec a . vec b .

If vec aa n d vec b are two unit vectors and theta is the angle between them, then the unit vector along the angular bisector of vec a and vec b will be given by a. ( vec a- vec b)/(cos(theta//2)) b. ( vec a+ vec b)/(2cos(theta//2)) c. ( vec a- vec b)/(2cos(theta//2)) d. none of these

If theta is the angle between two vectors vec a\ a n d\ vec b ,\ t h e n\ vec adot vec bgeq0 only when 0

For any two vectors vec a and vec b , prove that (vec a xx vec b )^2= |vec a |^2 |vec b|^2 -(vec a. vec b)^2