PLEASE I NEED ANSWER WITH EXPLANATION FAST, I HAVE EXAM IN 2 HOURS...

Q]

(a) The first five terms of a sequence are 1, 3, 6, 10, 15.
The 'nth' term of this sequence is 1/2 x n(n+1).
Find the 19th Term.

(b) Write down an expression, in terms of 'n', for the 'nth' term of the sequence: 3, 6, 10, 15, 21, ....

Question

PLEASE I NEED ANSWER WITH EXPLANATION FAST, I HAVE EXAM IN 2 HOURS...

Q]

(a) The first five terms of a sequence are 1, 3, 6, 10, 15.
The 'nth' term of this sequence is 1/2 x n(n+1).
Find the 19th Term.

(b) Write down an expression, in terms of 'n', for the 'nth' term of the sequence:   3, 6, 10, 15, 21, ....

bibby · Answer

In part A, n is 19. just plug it into the equation

disco619 · Answer

hmm intradasting...

disco619 · Answer

= 190 [Ans] (correct)

What about (b)

bibby · Answer

20*19 = 380
1/2x380 = something that you didn't get

disco619 · Answer

??? I did the equation on a paper...
So what about (b)?

bibby · Answer

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