Posted by M.A. on Saturday, June 13, 2009 at 7:44am.
You have an "arithmetice sequence"
with the first number as 57 and a common difference of 2
the general term of any arithmetic sequence is given by
term(n) = a + (n-1)d, were n is the term number,
a is the first term, and
d is the common difference
so we have 1233 = 57 + (n-1)(2)
1233 = 57 + 2n - 2
1178 = 2n
n = 589
so there are 589 terms
I have actually printed out all of the numbers "57, 59, 61,63, all the way to 1233". There are 619 numbers. I double checked for errors that all of the numbers were correct. There are actually 619 numbers, for real. The mathematical formula you used does not match with the actual print-out of the real numbers. Please explain.
Can you run the real numbers as a double-check for your formula and see what shows up on a list of counted numbers? The formula does not appear to agree with reality.
sorry, this is a well-known formula and is correct.
There is no need to "run the the real numbers as a double-check"
let's check some of the numbers
e.g.
term(4) = 57 + (4-1)(2)
= 57 + 6 = 63 ...check!
term(612) = 57 + (612-1)(2) = 1278
This was you answer, but obviously doesn't verify
my answer:
term(589) = 57 + (589-1)(2)
= 57 + 1176
= 1233 ... check!!
here is a quick way to verify my answer
and to show your list has an error in it.
go to Excel
enter 57 into A1
in A2 enter the formula "= A1 + 2"
highlight columns A down to your 612
and use the 'copy down' to enter the formula in all those cells
now look in A589
Well, well....
Just noticed that 'Writeacher' already gave you a detailed series of steps how to do this in Excel.
http://www.jiskha.com/display.cgi?id=1244858200
In doing the Excel list, my column A589 has the number 1177 listed. In checking the list of real numbers again, I have found another major error. Thank you so much for your patient help in working with this mathematically challenged individual.But at least I am learning!
check that in your Excel list such values as A1 = 57 ,A2 = 59 etc are correct
if A4 = 63 but A589 is not equal to 1233 there has to be something wrong with your cell formula, or God forbid, your EXcel program
25+10+15+15=