# Thread: logarithmic expressions help

1. ## logarithmic expressions help

is this right?

log(X^2 + 3X + 2) - 2log(X+1)
=
log(X+2)(X+1)
______________

log(X+1)^2

=

(X+2)
_________

(X+1)

Can you help with these

ln(ex)

answer is 1 + LN X according to book, would like to know how to solve.

and

ln(xe^x)

I will probably have more, I have notes and some of my questions have answers in the book(odd ones), but no matter how much I think I know I always get something wrong.

2. Hi kenny87,

Originally Posted by kenny87
is this right?

$\log(x^2 + 3x + 2) - 2 \log(x+1)=\log \frac{(x+2)(x+1)}{(x+1)^2}=\log \frac{x+2}{x+1}$
Careful not to cancel the log out there in your final step.

Originally Posted by kenny87

Can you help with these

$\ln(ex)
$

answer is $1 + \ln x$ according to book, would like to know how to solve.
$\ln (ex)= \ln e + \ln x = 1 + \ln x$

Remember: $\ln e = 1$

Originally Posted by kenny87

and

$\ln(xe^x)$

I will probably have more, I have notes and some of my questions have answers in the book(odd ones), but no matter how much I think I know I always get something wrong.
$\ln(xe^x)=\ln x + \ln e^x = \ln x+ x$

3. Careful not to cancel the log out there in your final step.
you lost me there, did I do something wrong?

Anyways, thanks for the help.

4. Originally Posted by kenny87
is this right?

log(X^2 + 3X + 2) - 2log(X+1)
=
log(X+2)(X+1)
______________

log(X+1)^2

=

(X+2)
_________

(X+1)

After your last = sign, there's no "log". Where did it go?

5. oops, I knew its just I am not use to typing math problems on a keyboard and forgot.

6. deleted