Question

5. Which of the following gives us the value of
seventeenth triangular number
1+2+3+....+ 17 (b) 1 + 2 + ... +8
(C) 1 + 3 + 5 +...+ 17 (d) 2 + 4 + 8 + ..... +34.and how​

Answer 1

Answer:

A triangular number or triangle number counts objects arranged in an equilateral triangle. The nth triangular number is the number of dots in the triangular arrangement with n dots on a side, and is equal to the sum of the n natural numbers from 1 to n. The sequence of triangular numbers (sequence A000217 in the OEIS), starting at the 0th triangular number, is

0, 1, 3, 6, 10, 15, 21, 28, 36, 45, 55, 66, 78, 91, 105, 120, 136, 153, 171, 190, 210, 231, 253, 276, 300, 325, 351, 378, 406, 435, 465, 496, 528, 561, 595, 630, 666...

mark as brainlist.