# Log qn

• September 26th 2012, 04:47 AM
ZGOON
Log qn
Hi,

Can anyone help me with Q7b??

It involve trigo and log. I'm stuck with it! HELP Please
• September 26th 2012, 06:05 AM
emakarov
Re: Log qn
It's not as scary as it seems. Divide the numerator and the denominator of the left-hand side by the numerator and use $\log_b a = \frac {1} {\log_a b}$ (*). Using $\log_aa=1$, simplify the left-hand side to $\frac{1}{\log_{\sin\theta}\cot\theta}$.

Apply $\log_b a = {\log_d a \over \log_d b}$ and (*) to the right-hand side and you are almost done.

A list of logarithmic identities is here.
• September 26th 2012, 06:40 AM
ZGOON
Re: Log qn
hmmm... but how do i divide the denominator?

sorry i really suck at maths
• September 26th 2012, 06:49 AM
emakarov
Re: Log qn
Quote:

Originally Posted by ZGOON
hmmm... but how do i divide the denominator?

Use the fact that $(\sqrt{a}-\sqrt{b})/\sqrt{b}=\sqrt{a/b}-1$.