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Vector Algebra

Question
CBSEENMA12033989

Let straight a with rightwards arrow on top space equals space straight i with hat on top space plus space 2 space straight j with hat on top and straight b with rightwards arrow on top space equals space 2 straight i with hat on top space plus space straight j with hat on top. Is open vertical bar straight a with rightwards arrow on top close vertical bar space equals space open vertical bar straight b with rightwards arrow on top close vertical bar space ? Are the vectors straight a with rightwards arrow on top space and space straight b with rightwards arrow on top equal?

Solution
straight a with rightwards arrow on top space equals space straight i with hat on top space plus space 2 space straight j with hat on top comma space space space straight b with rightwards arrow on top space equals space 2 straight i with hat on top space plus space straight j with hat on top
                   open vertical bar straight a with rightwards arrow on top close vertical bar space equals space square root of left parenthesis 1 right parenthesis squared plus left parenthesis 2 right parenthesis squared end root space equals space square root of 1 plus 4 end root space equals space square root of 5
open vertical bar straight b with rightwards arrow on top close vertical bar space equals space square root of left parenthesis 2 right parenthesis squared plus left parenthesis 1 right parenthesis squared end root space equals space square root of 4 plus 1 end root space equals space square root of 5
therefore space space space space space space open vertical bar straight a with rightwards arrow on top close vertical bar space equals space open vertical bar straight b with rightwards arrow on top close vertical bar
straight a with rightwards arrow on top space and space straight b with rightwards arrow on top are not equal as their corresponding components are distinct.