Question

What is the angle between A i j k, B 2i 2 j 2k.

Answer 1

$\mathfrak{\huge\underline{Answer:}}$

a=i+2j-k

b=-i+j-2k

as we know that,for two given vectors a

and b,we have:-

a.b=lal*Ibl*cos a^b

where a^b is the angle between the

vectors a and b

so, a.b= 1*-1+2*1+-1*2=3

lal=(1+4+1)^1/2=V6

Ibl=(1+1+4) 1/2=V6

from the given equation,we have

3=16*16*cos a^b

So,cos a^b=3/6=1/2

so angle between the vectors is 60

degree