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This log equation

  • #1

Homework Statement



2.3(1.2)^5z = 3(4.1)^z solve for z

Homework Equations



the properties of logarithm

The Attempt at a Solution


okay I first divided the 3 with 2.3 and got 1.304 then i brough the 5z and the z down which gives me 5z log(1.2)=1.304 z log(4.1) then i plugged log of 1.2 and 4.1 into the calculator and got .079 and .613 which makes the equation 5z(.079)=1.034z(.613) i then distributed and got .395z=.8z which doesnt give me an answer is the answer no solutions or did i do sumthing wrong?
 

Answers and Replies

  • #2
13
0
Hint: log( A B^z ) = log(A) + log(B^z) = log(A) + z log(B)
 
  • #3
290
2
...which doesn't give me an answer. Is the answer that there are no solutions or did I do something wrong?
Yes, there are no solutions to this equation. Unless you used z because you want complex solutions, in which case the properties of logarithms aren't the same.
 
  • #4
29
0
Yes, there are no solutions to this equation.
There is most definitely a solution to this equation. Take giant_bog's advice in using that log expansion rule.
 
  • #5
290
2
There is most definitely a solution to this equation. Take giant_bog's advice in using that log expansion rule.
You are correct. My mistake.
 

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