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Question

Mathematics Question on Vector Algebra

The value of [(ab)(bc)(ca)][( a - b )( b - c )( c - a )] is equal to

A

11

B

22

C

00

D

2[abc]2[ a b c ]

Answer

00

Explanation

Solution

[(ab)(bc)(ca)]\therefore[(a-b)(b-c)(c-a)]
=(ab)[(bc)×(ca)]=(a-b) \cdot[(b-c) \times(c-a)]
=(ab)[b×cb×ac×c+c×a]=(a-b) \cdot[b \times c-b \times a-c \times c+c \times a]
=(ab)[b×cb×a+c×a]=(a-b) \cdot[b \times c-b \times a+c \times a]
[c×c=0][\because c \times c=0]
=a[b×c]a[b×a]+a[c×a]=a \cdot[b \times c]-a \cdot[b \times a]+a \cdot[c \times a]
b[b×c]+b[b×a]b[c×a]-b \cdot[b \times c]+b \cdot[b \times a]-b \cdot[c \times a]
=[abc]0+0+0[bca]=[a b c]-0+0+0-[b c a]
=[abc][abc]=[a b c]-[a b c]
=0=0