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Mathematics 17 Online
OpenStudy (anonymous):

log3(3.3)=?

OpenStudy (anonymous):

Rewrite in exponential notation. \[3^{x} = 3.3\] Take the log of both sides. \[\log_{}3^{x} = \log_{} 3.3\]

OpenStudy (anonymous):

Solve for x. \[x \log_{} 3 = \log_{}3.3\]

OpenStudy (anonymous):

ok

OpenStudy (anonymous):

so what is its answer?

OpenStudy (anonymous):

I already gave it to you. Just solve for x. You just have to divide both sides by log(3)

OpenStudy (anonymous):

3= 3?

OpenStudy (anonymous):

No. x = log(3.3) / log(3)

OpenStudy (anonymous):

x=3

OpenStudy (anonymous):

That is the answer.

OpenStudy (anonymous):

but its result is 1.087

OpenStudy (anonymous):

Right. If you take 3^(1.087) it should equal 3.3

OpenStudy (anonymous):

ok

OpenStudy (anonymous):

think what you need here is the almighty change of base formula. use \[\log_b(A)=\frac{\log(A)}{\log(b)}\] so use \[\frac{\log(3.3)}{\log(3)}\]

OpenStudy (anonymous):

Same result.

OpenStudy (anonymous):

yes but without exponentiating and then taking the log again.

OpenStudy (anonymous):

If you don't like memorizing formulas, you can use definitions of what logs and exponentials are.

OpenStudy (anonymous):

ok

OpenStudy (anonymous):

point is that all logs are the same, in other words to solve \[b^x=A\] for x you go right to \[x=\frac{\ln(A)}{\ln(b)}=\frac{\log(A)}{\log(b)}\]

OpenStudy (anonymous):

is it formular?

OpenStudy (anonymous):

all logs are the same. they only differ by a constant. so you can use any one you like

OpenStudy (anonymous):

in practice however, you only have two on your calculator, log base ten written as log and log base e written as ln so as a practical matter you use one of those

OpenStudy (anonymous):

but i don't understand how you have its result is 1.087

OpenStudy (anonymous):

well you do not know what power to raise 3 to in order to get 3.3 that is what you are looking for and why you need a calculator

OpenStudy (anonymous):

That's what the definitions of a log is. \[\log_{3}3.3 = 1.087 means 3^{1.087} = 3.3 \]

OpenStudy (anonymous):

so you take out the calculator and type in \[\log(3.3)\div \log(3)\] to get your answer

OpenStudy (anonymous):

or you can type in \[\ln(3.3)\div \ln(3)\] either way

OpenStudy (anonymous):

what is mean In?

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