SOLUTION: Ok so i'm studying for a math test and it's about logarithms and on the review it has a question log base n 1/625=-4 I have no idea how to solve this.

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Question 437463: Ok so i'm studying for a math test and it's about logarithms and on the review it has a question log base n 1/625=-4

I have no idea how to solve this.

Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


I am going to go way out on a limb here and presume that you have:



And that you want to solve for . In this case, it is fairly obvious what you want, but I could well have taken the position that since you didn't bother to ask, I shouldn't be forced to guess. In return for our help, you have an obligation to communicate accurately and completely.

Remember the definition of the logarithm function:



With your given numbers:



But also remember:



Therefore:



Hence:



Use your calculator.

Super Double Plus Extra Credit Taking the 4th root of 625 will result in two real number values, one positive and the other negative (you are taking the square root of the square root after all). Explain why the negative root (and any complex number roots for that matter) must be discarded in the case of this problem.

John

My calculator said it, I believe it, that settles it
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