Friday

November 28, 2014

November 28, 2014

Posted by **Daniel** on Monday, October 9, 2006 at 10:43pm.

1st 2nd 3rd 4th

. . . .

. . . . . . . . . . . .

. . . .

Is there a simple formula for this?

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, 703, 741, 780, 820, 861, 903, 946, 990, 1035, 1081, 1128, 1176, 1225, 1275, 1326, 1378, 1431

Search on Trianglular numbers on Google.

[k(k+1)]/2 is the general formula.

k=1 gives (1*2)/2=1

k=2 gives (2*3)/2=3

k=10 (10*11)/2 = something you can do.

k=20 (20*21)/2 = something you can do.

k=100 (100*101)/2 = something you can do.

Prove the formula by induction.

HELP MATH

**Answer this Question**

**Related Questions**

Math - A triangular number is a number that can be represented by dots arranged ...

Maths - Please Could someone tell me what: 1. A square number is 2. A cube ...

Math - Mark read that the ancient Greeks use to arrange pebbles to represent ...

Math - I need help with making a formula..? This is what I put.. "The 100th ...

math - The triangular numbers are the numbers 1, 3, 6, 10, 15, . . .; the square...

MATH - The triangular numbers are the numbers 1, 3, 6, 10, 15, . . .; the square...

algebra - The formula t(n+1)over 2 will determine a triangular number, where n ...

Math (check answers) - which three-dimensional figure has all triangular faces? ...

math - smallest of two triangular numbers whose sum and difference are also ...

Math - Which of the following has exactly four faces? A. cone B. square C. ...