MCQ
$[(a \times b) \times (b \times c)\,(b \times c) \times (c \times a)\,(c \times a) \times (a \times b)] = \,$
  • A
    ${[a\,\,b\,\,c]^2}$
  • B
    ${[a\,\,b\,\,c]^3}$
  • ${[a\,\,b\,\,c]^4}$
  • D
    None of these

Answer

Correct option: C.
${[a\,\,b\,\,c]^4}$
c
(c) We have $(a \times b) \times (b \times c)$$ = ((a \times b)\,.\,c)b - ((a \times b)\,.\,b)c = [a\,b\,c]b$

$(b \times c) \times (c \times a) = ((b \times c)\,.\,a)c - ((b \times c)\,.\,c)a = [\,b\,c\,a]\,c$

$(c \times a) \times (a \times b) = ((c \times a)\,.\,b)a - ((c \times a)\,.\,a)b = [c\,a\,b]\,a$

$\therefore \,\,\,[(a \times b) \times (b \times c)(b \times c) \times (c \times a)(c \times a) \times (a \times b)]$

$ = [[a\,b\,c]\,a\,[a\,b\,c]\,b\,[a\,b\,c]\,c]$$ = {[a\,b\,c]^3}[a\,b\,c] = {[a\,b\,c]^4}.$

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