Old dog new tricks ...e^-x/y how do you solve for x?

[glaevsky]

I'm a cell biologist looking at the exponential decay of a light field, and I'm a bit over my head. Being 50, I figured I can cheat on my homework. Little help please? Thanks, Gary

 

[pka]

I'm a cell biologist looking at the exponential decay of a light field, and I'm a bit over my head. Being 50, I figured I can cheat on my homework. Little help please? Thanks, Gary

Not sure exactly what you are asking.
If \(\displaystyle d=e^{\frac{-x}{y}}\) then \(\displaystyle x=-y\ln(d)\).

 

[glaevsky]

Yes!!!

Thank you!!!

 

[mmm4444bot]

I'm not sure how pka's response answers the question "how do you solve?", but you seem to be satsified with the response.

Can you now solve the following equation for k?

399000 = 344.3*e^(-k/5)

PS: Note that we enclose an exponent inside parentheses, when the exponent consists of more than a single symbol.