Rule of 72 in Exponential and logarithmic functions

[shizidushu]

In http://calculuswithjulia.github.io/precalc/exp_log_functions.html

Typo related to the following line:
The amount of time to double an investment that grows according...

The logarithm base should be e:

The amount of time to double an investment that grows according to $P_0 e^{rt}$ solves $P_0 e^{rt}=2P_0$, or $rt=\ln^{(2)}$. So we get $t=\ln^{(2)}/r$. As $\ln^{(2)}$ is

log(2)

[jverzani]

In Julia log() is natural log. So log(2) uses base e.

On Mon, Dec 23, 2019 at 2:27 AM shizidushu ***@***.***> wrote: In http://calculuswithjulia.github.io/precalc/exp_log_functions.html Typo related to the following line: The amount of time to double an investment that grows according... The logarithm base should be e: The amount of time to double an investment that grows according to $P_0 e^{rt}$ solves $P_0 e^{rt}=2P_0$, or $rt=\ln^{(2)}$. So we get $t=\ln^{(2)}/r$. As $\ln^{(2)}$ is log(2) — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#18?email_source=notifications&email_token=AADG6TF3CBG4XQLTUHUDWJ3Q2BR7HA5CNFSM4J6QYCSKYY3PNVWWK3TUL52HS4DFUVEXG43VMWVGG33NNVSW45C7NFSM4ICIOK7Q>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AADG6TFEXZHHMTBSROTZBTDQ2BR7HANCNFSM4J6QYCSA> .

-- John Verzani Department of Mathematics College of Staten Island, CUNY verzani@math.csi.cuny.edu