Sequence

Feb 2010
52
0
If a sequence is:

a. -2,2,-2,2,-2,....

b. 4,2,(4/3),1,(4/5),...

How do I prove the common difference, d, using the Arithmetic Sequence for these 2 problems?

ie.
a3 = a1 (n - 1)d

So would problem a be:

-2 = -2(3-1)d ?
Im getting 1/2 for d but its not the right answer

Thanks
 
Oct 2009
4,261
1,836
If a sequence is:

a. -2,2,-2,2,-2,....

b. 4,2,(4/3),1,(4/5),...

How do I prove the common difference, d, using the Arithmetic Sequence for these 2 problems?


You can't because none of these sequences is arithmetic: the first one is a (rather boring) geometric sequence with common ration = -1, and the second one is just a sequence...

Tonio



ie.
a3 = a1 (n - 1)d

So would problem a be:

-2 = -2(3-1)d ?
Im getting 1/2 for d but its not the right answer

Thanks
.
 
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