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# Hey, I have a maths research assignment(grade 9) and I was wondering how I can find the first three terms of a geometric progression, knowin

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Hey, I have a maths research assignment(grade 9) and I was wondering how I can find the first three terms of a geometric progression, knowing that r=3, term2= 9 & term12=531441 Thanks

Guest Jun 22, 2015

#1
+26470
+5

If the first term is "a" then the n'th term is a*rn-1 so  you have:

From term 2: a*3 = 9 so a = 3; and this gives the 12th term as 3*311 = 531441.

You now have the first and second terms.  I'll leave you to work out the third term.

.

Alan  Jun 22, 2015
Sort:

#1
+26470
+5

If the first term is "a" then the n'th term is a*rn-1 so  you have:

From term 2: a*3 = 9 so a = 3; and this gives the 12th term as 3*311 = 531441.

You now have the first and second terms.  I'll leave you to work out the third term.

.

Alan  Jun 22, 2015

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