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

Question:
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.

Thank-you!

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.

Cheers,
Harley

 

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