Maths [natural logarithms] help

[werto165]

https://goo.gl/photos/MAwcs6S476waCopWA

Confused do I need to always take the modulus of a negative term? Or would I just say it's undefined?

[T.Vengeance]

Do the difference of the logs. Then divide the inside and solve.

 

Oh wait I get it. Sorry I didn't read it properly.

[as96]

I can't see too much of the image, but ln( a ) + ln( b ) = ln(ab) and ln( a ) - ln( b ) = ln( a/b ) if that's what you are asking.

[werto165]

I can't see too much of the image, but ln( a ) + ln( b ) = ln(ab) and ln( a ) - ln( b ) = ln( a/b ) if that's what you are asking.

T.Vengeance

What I'm asking is i have ln(-e^(-lambda t)) do I take the absolute value i.e

ln(|-e^(-lambda t)|) so in affect it turns to

ln(e^(-lambda t))

Is this the case with all negative numbers that you take a log with?

[T.Vengeance]

T.Vengeance

What I'm asking is i have ln(-e^(-lambda t)) do I take the absolute value i.e

ln(|-e^(-lambda t)|) so in affect it turns to

ln(e^(-lambda t))

Is this the case with all negative numbers that you take a log with?

No cause if you work backwards, you actually get a totally different equation. And also ln(-e^(-lamda t)) is undefined too because when you break it up, it's Ln(-1)+Ln(e^lamda t). I don't think it's possible to get from the top to the bottom.

[as96]

Logs of negative numbers are undefined, so you have to use complex logarithms as far as I know.

[werto165]

No cause if you work backwards, you actually get a totally different equation. And also ln(-e^(-lamda t)) is undefined too . I don't think it's possible to get from the top to the bottom.

So then this question is wrong? https://goo.gl/photos/GMWPzDEjjHg8Rqw2A