SOLUTION: I am stumped. I know there must be an answer. I studied my exponents like 2^3 = 8 and the inverse of that is 3 = log2(8) and the radical for that is 3 root 8 = 2. But with the s

Algebra ->  Logarithm Solvers, Trainers and Word Problems -> SOLUTION: I am stumped. I know there must be an answer. I studied my exponents like 2^3 = 8 and the inverse of that is 3 = log2(8) and the radical for that is 3 root 8 = 2. But with the s      Log On


   



Question 635629: I am stumped. I know there must be an answer. I studied my exponents like
2^3 = 8 and the inverse of that is 3 = log2(8) and the radical for that is
3 root 8 = 2. But with the same theory. I was wondering how log 7 = .8451.
10^.8451 = 7.000031591 in the radical form and in the fraction form works as well but I cannot figuire it out in the exponential form. I know there are
formulas and something like b()-1=b(something but can anyone explain how
10^.8451 which is log of 7 is worked out. Do I have to become a master guru just
to get through this.

Answer by jsmallt9(3758) About Me  (Show Source):
You can put this solution on YOUR website!
I'm not sure I understand what your question is.

If the question is "How does one find the value of a logarithm?", then there are two main options:
  • On your own, without help. When finding logarithms on your own they break down into two groups:
    • Logarithms that can be found with a reasonably small amount of effort. In this category would be logs like log%282%2C+%288%29%29 or log%289%2C+%2881%29%29 or log%2816%2C+%284%29%29 (1/2), etc. These logs are relatively easy because it is not too difficult to figure out what power of the base results in the argument.
    • Logarithms which would require a major effort to calculate. In this group would be logs like log(7). It is not easy to find out what power of 10 results in a 7. Since 10%5E0+%3C+7+%3C+10%5E1 you know that log(7) will be between 0 and 1. After that it get difficult. One way to find log's (or sin's, cos's, etc.) is to use what are called "Taylor's series". (There may be other ways but I cannot think of them at the moment.) Taylor's series use advanced Math (Calculus) to "convert" something like a log (or sin or cos, etc.) into an expression for a decimal approximation that could be calculated by hand. If you want to know more and you know about derivatives then look up "Taylor's series".
  • With help. Use a calculator or a table of logarithms. This is easy but keep in mind that the calculator will give you decimal approximations most of the time. (This is why 10%5E0.8451 is not exactly 7.) And when it does give you an exact answer it may be difficult to tell that it is not an approximation. So I recommend finding logs by hand when possible and using calculators for the rest.