Question

The angle between two vectors -2i`(cap) +3j cap +k cap and i cap +2j cap -4k cap is

Answer 1

We will find the angle between this two vector using scalar product or dot product

first vector=-2i+3j+k

second vecotor=i+2j-4k

dot product of these two vectors=-2i×i+3j×2j+-4k×k=-2+6-4=0

also,we know,dot product=abcos∅

so

abcos∅=0

cos∅=0

∅=90

Hence the angle between the given two vectors is 90°

{hope it helps}