If `veca and vecb` are two unit vectors such that `veca + 2vecb and 5 veca - 4vecb` are perpendicualar to each other, then the angle between `veca and vecb` is

If veca and vecb are two unit vectors such that veca+2vecb and 5veca-4vecb are perpendicular to each other, then the angle between veca and vecb is

If veca and vecb are two unit vectors such that veca+2vecb and 5veca-4vecb are perpendicular to each other then the angle between veca and vecb is (A) 45^0 (B) 60^0 (C) cos^-1(1/3) (D) cos^-1(2/7)

If veca and vecb are unit vectors such that 2veca-4vecb and 10veca+8vecb are perpendicular to each other, then find the angle between these two vectors.

If veca and vecb are non - zero vectors such that |veca + vecb| = |veca - 2vecb| then

If veca . vecb =ab then the angle between veca and vecb is

If veca, vecb, vecc are vectors such that veca.vecb=0 and veca + vecb = vecc then:

If veca and vecb are unequal unit vectors such that (veca - vecb) xx[ (vecb + veca) xx (2 veca + vecb)] = veca+vecb then angle theta " between " veca and vecb is

veca and vecb are two vectors such that |veca|=1 ,|vecb|=4 and veca. Vecb =2 . If vecc = (2vecaxx vecb) - 3vecb then find angle between vecb and vecc .

If veca , vecb are unit vectors such that the vector veca + 3vecb is peependicular to 7 veca - vecb and veca -4vecb is prependicular to 7 veca -2vecb then the angle between veca and vecb is

If veca, vecb are unit vectors such that |veca +vecb|=1 and |veca -vecb|=sqrt3 , then |3 veca+2vecb |=