Find the sum: 1+2+3+ ... +9999+10000.

It's an arithmetic sequence.



Find which term is 10000:

10000 is the 10000th term.

This requires the formula for summation of an arithmetic sequence, which was first derived by Gauss, since the sequence is of the form .

a = 1 (the first term)
L = 10000 (the last term)
n = 10000 (the number of terms summed)

The formula is:



Therefore the sum is 50005000

I hope this helps

Angle onp = 43°angle lno = 137°angle mnp = 137°

Ais the answer to your ques