Question

1+ 3+ 6 + 10 + ........... ... n terms:​

Answer 1

Answer:

Step-by-step explanation:

Let the required sum be S

Shifting he whole sequence by 1 place and subtracting S-S=0=1+2+3+...+(Tn-Tn-1)-Tn

From this we get Tn as a general term.

After this simplifying using summation and known result

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