The two questions are here, they're probably easy but I'm having a brain freeze lol

http://img29.imageshack.us/img29/5626/file.png

The 4(c) sequence is 5, 7, 9, 11....

The 4(d) sequence is 5, -10, 20, -40.....

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- May 13th 2010, 04:00 PMbrumby_3Find a formula for the sequence....
The two questions are here, they're probably easy but I'm having a brain freeze lol

http://img29.imageshack.us/img29/5626/file.png

The 4(c) sequence is 5, 7, 9, 11....

The 4(d) sequence is 5, -10, 20, -40..... - May 13th 2010, 04:38 PMArchie Meade
Hi brumby_3,

1st one

is an ARITHMETIC SEQUENCE.

To sum all the terms of the sequence, the sum is

which is the average value multiplied by the number of terms.

2nd one

The next term is the previous one multiplied by

This is a GEOMETRIC SEQUENCE.

The sum of these terms is

which is

where "a"=1st term, "r"=common ratio.