Question 128055
natural logs (base e) are used for continuous compounding __ A=Pe^(rt)


the compound interest calculation is exponential, so depending on what quantity you're trying to find,
__ logs are involved


the only difference between "logs" (common logarithms) and natural logs is the base
__ common logs are base 10, natural logs are base e (Euler's number)


A=P(1+r)^n where A=amount; P=principle (starting amount);
__ r=interest rate per compounding period; n=number of compounding periods


18000=9000(1+r)^9


dividing by 9000 __ 2=(1+r)^9


taking log __ log(2)=9(log(1+r))


dividing by 9 __ (log(2))/9=log(1+r)


taking antilog __ 10^(log(2)/9)=1+r __ 10^(log(2)/9)-1=r