IIT JEE , AIEEE Forum - Mathematics , Algebra

Aatish

i could not get the logic why you used triangular numbers in the problem

1+2+2+3+3+3+4+4+4+4+..........

plz explain it in dtail quickly

amaron

consider the sequence,
1+2+2+3+3+3+4+4+4+4+..........

where is the last integer of any type ending?

the last 1 ends in the first place <1 is a triangular number>

the last 2 ends in the third place <3 is a triangular number>

the last 3 ends in the sixth place <6 is a triangular number> ..so on

obviously,one can see that the last 'n' will end in (n)(n+1)/2.

therefore in my summation , i want to find the.......

Aatish

thanks for your reply amaron

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