Subject: logs
Name: Jennifer
Who is asking: Student
Level: Secondary

Hi I have a test tomorrow and I was wondering if you could help me with these two problems.

  1. Explain how to express y in terms of x if log3y=4log3(2X)

  2. The LN key on your scientific calculator is not working, but the ex and LOG keys are. Write directions for calculating a natural logarithm using the ex and LOG keys. Explain why these directions will get you the right answer.


Hi Jennifer,
The crutial property of logarithms that is important in both problems is that

log ab = b log(a)

  1. Using this property log3y = 4log3(2X) =log[3(2x)]4 and thus 3y = [3(2x)]4

  2. y = ln(x) is equivalent to ey = x. Now take the log of both sides and solve for y.



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