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Find the middle the terms in the expansion of `(5x-7y)^(7)` |
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Answer» Since n is an odd number, the expansion contains two middle terms `((7+1)/(2))th and ((7+3)/(2))` th terms are the two middle terms in the expansion of `(5x-7y)^(7)` `t_(4)=T_(3+1)=(-1)^(3)""^(7)C_(3)(5x)^(7-3)(7y)^(3) =-""^(7)C_(3)(5x)^(4)(7y)^(3)` =`T_(5)=T_(4+1)=(-1)^(4)*""^(7)C_(4)(5x)^(7-4)*(7y)^(4)=""^(7)C_(4)(5x)^(3)(7y)^(4)` |
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