Find `|vec a|` and `|vec b|` if `(vec a + vec b).(vec a - vec b) = 3` and `2|vec b| = |vec a|`.

Find |veca| and |vec b| , if (vec a + vec b).(vec a - vec b ) = 7 and |vec a| = 7|vec b|

Find | vec a|a n d| vec b|,if( vec a+ vec b)dot( vec a- vec b) = 8 , | vec a|=8| vec b|dot

Show that (vec a - vec b) xx (vec a + vec b) = 2 (vec a xx vec b)

Find |vec a - vec b| , if two vectors vec a and vec b are such that |vec a | = 2, |vec b| = 3 and vec a.vec b = 4 .

If veca = hat i - hat j + hat k, vec b = 2 hat i + hat j + 3 hat k , then (i) Find vec a + vec b , vec a - vec b and vec a. vec b . (ii) Find (vec a + vec b) xx (vec a - vec b) . (iii) Find a unit vector perpendicular to both vec a + vec b and vec a - vec b .

If non-zero vectors vec aa n d vec b are equally inclined to coplanar vector vec c ,t h e n vec c can be a. (| vec a|)/(| vec a|+2| vec b|)a+(| vec b|)/(| vec a|+| vec b|) vec b b. (| vec b|)/(| vec a|+| vec b|)a+(| vec a|)/(| vec a|+| vec b|) vec b c. (| vec a|)/(| vec a|+2| vec b|)a+(| vec b|)/(| vec a|+2| vec b|) vec b d. (| vec b|)/(2| vec a|+| vec b|)a+(| vec a|)/(2| vec a|+| vec b|) vec b

If vec a_|_ vec b , then vector vec v in terms of vec aa n d vec b satisfying the equation s vec v . vec a=0a n d vec v . vec b=1a n d[ vec v vec a vec b]=1 is a. vec b/(| vec b|^2)+( vec axx vec b)/(| vec axx vec b|^2) b. vec b/(| vec b|^2)+( vec axx vec b)/(| vec axx vec b|^2) c. vec b/(| vec b|^2)+( vec axx vec b)/(| vec axx vec b|^2) d. none of these

Let vec aa n d vec b be two non-zero perpendicular vectors. A vecrtor vec r satisfying the equation vec rxx vec b= vec a can be vec b-( vec axx vec b)/(| vec b|^2) b. 2 vec b-( vec axx vec b)/(| vec b|^2) c. | vec a| vec b-( vec axx vec b)/(| vec b|^2) d. | vec b| vec b-( vec axx vec b)/(| vec b|^2)

If vec a is parallel to vec bxx vec c , then ( vec axx vec b)dot( vec axx vec c) is equal to a. | vec a|^2( vec b . vec c) b. | vec b|^2( vec a . vec c) c. | vec c|^2( vec a . vec b) d. none of these

Show that ( vec a- vec b)xx( vec a+ vec b)=2( vec axx vec b)dot