Thursday, May 3, 2007

sequences

hi sir. i was able to solve the problem with the blog.

im havin problems writting an explicit definiton for a problem. someone thats able to help me on that, please give me a little help and teach me at least a little bit on how todo do it, so that i get better on it.

frank garcia
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1 comment:

MAC said...

Frank, the goal is to be able to solve these problems without memorizing specific formulas, only by truly understanding what it is being said. With explicit definitions, we can find the value of any term in the sequence without having to add or multiply each previous term to get the next.

The explicit definition for an arithmetic sequence is:
t(n)=t1+(n-1)*d

Here, you plug for "n" the term you want to find, and add the value of the first term to the number of jumps, which is always the number of the term minus one, multiplied by the distance between each jump.

So if an arithmetic sequence is 2,4,6,8...

you find out that term 1 is 2, and that the diference between each number is 2.
So for the sequence you plug in

t(n)= 2 + (n-1)*2

To find the value of the 10th term, you plug 10 in for n.
t(10)=2+(10-1)*2
t(10)=2+(9)*2
t(10)=2+18
t(10)=20

The 10th term would be 20.

I hope this can be of help... if you need something more in depth or anything ask me.

May 5, 2007 at 2:39 PM

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