PLEASE HELP!!! LOGRITHIMS

asweet1 · #1 $Old$ October 9th, 2008, 10:36 AM

Solve the following equations. Find the value of t correct to tow decimal points.

a) log(t-37)=3
my answer was 1001.56 but it says im wrong.

b)42e^0.8t=83e^0.2t
my answer was 1.13 but it also says im wrong

jaydee323 · #2 $Old$ October 9th, 2008, 11:02 AM

2 decimal places suggest you mean natural log (ln) not the base ten log

e^x is the antilog of ln x

does t= 57.09 xseem right?

masters · #3 $Old$ October 9th, 2008, 11:02 AM

Quote:

Originally Posted by asweet1 $View Post$

Solve the following equations. Find the value of t correct to tow decimal points.

a) log(t-37)=3
my answer was 1001.56 but it says im wrong.

b)42e^0.8t=83e^0.2t
my answer was 1.13 but it also says im wrong

a)log(t-37)=3

antilog(log(t-37))=antilog 3
t-37=1000
t=1037

b)

$42e^{0.8t}=83e^{0.2t}$

$\ln45+\ln e^{.8t}=\ln83+\ln e^{.2t}$

$\ln45+.8t=\ln83+.2t$

$.6t=\ln 83-\ln 45$

$t=\frac{\ln 83-\ln 45}{.6}$

$t=1.020296863$