Saturday, December 31, 2011

If log a = 35 and log b= 20 calculate : log (ab) , log (a/b) , log (1/a) and log (1/b)

Given that:


log a =
35


log b = 20


We need to
calculate the values of the following:


1.log
(ab)


We will use the logarithm properties to
solve.


We know that log a + log b  = log
ab


==> log ab = 35 + 20 =
55


==> log ab =
55


2. log
a/b


We know that: log a - log b = log
a/b


==> log a/b = 35 -20 =
15


==> log a/b =
15


log
(1/a)


Let us rewrite as a negative
exponent.


==> log 1/a = log
a^-1


Now we know that log a^b = b*log
a


==> log a^-1 = - log a = -
35


==> log (1/a) =
-35


4. log (1/b) = log b^-1 = -1*log b =
-1*20 = -20


==> log (1/b) =
-20

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