Summing ExponentsDate: 06/11/2002 at 16:57:23 From: Matt Subject: sequences A student multiplies successive powers of 3, 3^1 * 3^2 * 3^3 * ... gets an answer of 3^210. Find the last power of 3 in the list. I don't even know where to start. Is it a geometric series? Date: 06/11/2002 at 18:08:32 From: Doctor Ian Subject: Re: sequences Hi Matt, If you're not comfortable yet with the properties of exponents, you might want to look at Properties of Exponents http://mathforum.org/library/drmath/view/57293.html before reading further. Okay, now note that 3^1 * 3^2 * 3^3 * ... * 3^n = 3^(1 + 2 + 3 + ... + n) = 3^210 So the question is really asking you how many integers you have to add up to get a sum of 210. Can you take it from here? - Doctor Ian, The Math Forum http://mathforum.org/dr.math/ |
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