# Math SL IA - Logarithm bases

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[quote name='deissi' post='14634' date='Apr 7 2008, 09:15 AM']I did logarithm bases (type I), pretty simple. I'm not familiar with the BMI project, is it modelling (type II) or algebraic (type I)?[/quote]

Hey do you think you could help me with the logarithm bases? I dont quite understand what the are looking for when it says " let logaX=c and logbX=d. find the general statement that expresses logabX in terms of cd." thanks!

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[quote name='ajie1020' post='15694' date='Apr 28 2008, 11:05 PM']Hey do you think you could help me with the logarithm bases? I dont quite understand what the are looking for when it says " let logaX=c and logbX=d. find the general statement that expresses logabX in terms of cd." thanks! [/quote]

Well my first tip is to look at the logarithms before this logaX=c and logbX=d thing. If you were able to solve them and see the pattern, you know it for logaX=c and logbX=d as well.

If you're struggling with what is meant by log[sub]ab[/sub]x in terms of c and d, what they mean is for example:

say you have log[sub]a[/sub]x = log[sub]2[/sub]4 and log[sub]b[/sub]x = log[sub]8[/sub]4
The variables [i]c[/i] and [i]d[/i] are the answers of these two logarithms, and you should know how to find them. c = log[sub]2[/sub]4 and d = log[sub]8[/sub]4

For both these logarithms the value x, 8, stays the same, but the variable is a and b, the "small number".

So what is meant by log[sub]ab[/sub]x is a logarithm that combines the first two logarithms, log[sub]a[/sub]x and log[sub]b[/sub]x
Here ab = a * b, so using the examples we would find that ab = 2*8 = 16

If you still are in need of help, don't hesitate to ask !

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I understand what you're saying, deissi, but I'm still confused!! Maybe you can give me a hint on how to figure out the general statement... I'm confused, because in the sequences above the logaX=c logbX=d question, I wrote my answers in form p/q, found the pattern and figured out how to calculate the third term for each sequence (the numerator of all three answers is the same, but the demoninators are different; you add the denominators, i.e. q values, of the first two answers to find q of the third, right?)

But I don't understand how you can find the value of logabX, when the numerator is different and denominator is the same (as logaX = c/1 and logbX is d/1)... or maybe I'm taking the wrong approach to the question??

~~~

Ignore my post, I finally figured it out Edited by youcantstopthebeat

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do you happen to understand how to do the first part?
i'm not quite sure about the p and q thing and how to write out the answers.
thanks!

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