9ur grouping wrks only for even nos
for odd no there will be an unpaired sqr
12 - 22 + 32 - 42 + 52 - 62 +... = ?
solution :
LHS = (1-2)(1+2) + (3-4)(3+4) + (5-6)(5+6) + ... = - (1+2+3+4+5+6+...)
= - n(n+1)/2 .... Ans...
but for odd values of n, the above expression is not correct .... lyk substitute n=1,3,5... we get d sum as positive no. whereas the expression gives negative no. !!!
what's d fallacy ???
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3 Answers
9
1so dat cannot b concluded as an answer until n unless n is mentioned as an even no. rite !!!
