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Determinants

Question
CBSEENMA12034417

Prove that:
open vertical bar table row 1 1 1 row cell straight a squared end cell cell straight b squared end cell cell straight c squared end cell row cell straight a cubed end cell cell straight b cubed end cell cell straight c cubed end cell end table close vertical bar space equals space left parenthesis straight a minus straight b right parenthesis thin space left parenthesis straight b minus straight c right parenthesis thin space left parenthesis straight c minus straight a right parenthesis thin space left parenthesis straight a space straight b space plus space straight b space straight c space plus space straight c space straight a right parenthesis.

Solution

Let increment space equals space open vertical bar table row 1 cell space space 1 end cell cell space space 1 end cell row cell straight a squared end cell cell space space straight b squared end cell cell space space straight c squared end cell row cell straight a cubed end cell cell space space straight b cubed end cell cell space space straight c cubed end cell end table close vertical bar
         equals space open vertical bar table row 1 cell space space 0 end cell cell space space space 0 end cell row cell straight a squared end cell cell space space straight b squared minus straight a squared end cell cell space space space straight c squared minus straight a squared end cell row cell straight a cubed end cell cell space space straight b cubed minus straight a cubed end cell cell space space space straight c cubed minus straight a cubed end cell end table close vertical bar comma space space by space straight C subscript 2 minus straight C subscript 1 comma space space straight C subscript 3 minus straight C subscript 1
equals space open vertical bar table row cell straight b squared minus straight a squared end cell cell space space space space space space straight c squared minus straight a squared end cell row cell straight b cubed minus straight a cubed end cell cell space space space space space straight c cubed minus straight a cubed end cell end table close vertical bar comma space expanding space with space first space row.
equals space open vertical bar table row cell left parenthesis straight b minus straight a right parenthesis thin space left parenthesis straight b plus straight a right parenthesis end cell cell space space space space space left parenthesis straight c minus straight a right parenthesis thin space left parenthesis straight c plus straight a right parenthesis end cell row cell left parenthesis straight b minus straight a right parenthesis thin space left parenthesis straight b squared plus straight a squared plus ba right parenthesis end cell cell space space space space space space space left parenthesis straight c minus straight a right parenthesis thin space left parenthesis straight c squared plus straight a squared plus ca right parenthesis end cell end table close vertical bar
equals space left parenthesis straight b minus straight a right parenthesis thin space left parenthesis straight c minus straight a right parenthesis thin space open vertical bar table row cell straight b plus straight a end cell cell space space space space space space space space space straight c plus straight a end cell row cell straight b squared plus straight a squared plus ba end cell cell space space space space space space space space space straight c squared plus straight a squared plus ca end cell end table close vertical bar
equals space left parenthesis straight b minus straight c right parenthesis thin space left parenthesis straight c minus straight a right parenthesis thin space open vertical bar table row cell straight b plus straight a end cell cell space space space space space space space space space space space space space space space straight c minus straight b end cell row cell straight b squared plus straight a squared plus ba end cell cell space space space space space space space space space space space space straight c squared minus straight b squared plus ca minus ba end cell end table close vertical bar comma space by space straight C subscript 2 minus straight C subscript 1
equals space left parenthesis straight b minus straight a right parenthesis thin space left parenthesis straight c minus straight a right parenthesis thin space open vertical bar table row cell straight b plus straight a end cell cell straight c minus straight b end cell row cell straight b squared plus straight a squared plus ba end cell cell space space space space space space space space space space space space left parenthesis straight c minus straight b right parenthesis thin space left parenthesis straight c plus straight b right parenthesis plus left parenthesis straight c minus straight b right parenthesis space straight a end cell end table close vertical bar
equals space left parenthesis straight b minus straight a right parenthesis thin space left parenthesis straight c minus straight a right parenthesis thin space left parenthesis straight c minus straight b right parenthesis thin space open vertical bar table row cell straight b plus straight a end cell cell space space space space space space 1 end cell row cell straight b squared plus straight a squared plus ba end cell cell space space space space space space space space straight c plus straight b plus straight a end cell end table close vertical bar
equals left parenthesis straight a minus straight b right parenthesis thin space left parenthesis straight b minus straight c right parenthesis thin space left parenthesis straight c minus straight a right parenthesis space left square bracket bc plus straight b squared plus ab plus ca plus ab plus straight a squared minus straight b squared minus straight a squared minus ab right square bracket
equals space left parenthesis straight a minus straight b right parenthesis thin space left parenthesis straight b minus straight c right parenthesis thin space left parenthesis straight c minus straight a right parenthesis thin space left parenthesis straight a space straight b space plus space straight b space straight c space plus space straight c space straight a right parenthesis

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