Aptitude - Logarithm - Discussion
Discussion Forum : Logarithm - General Questions (Q.No. 5)
5.
| If log | a | + | log | b | = log (a + b), then: |
| b | a |
Answer: Option
Explanation:
| log | a | + log | b | = log (a + b) |
| b | a |
 log (a + b) = log |
 |
a | x | b |  |
= log 1. |
| b | a |
So, a + b = 1.
Discussion:
33 comments Page 4 of 4.
Siddhu said:
1 decade ago
We know that: log a + log b = log (a+b);
Similarly log(a/b) + log(b/a) = log (a/b * b/a);
We get log 1 bcoz all terms will get cancels
and log 1 = 0;
This is about L.H.S. So look at the R.H.S log(a+b) is there and we have to get R.H.S also zero it is possible when we get log 1 = log(a+b) so a+b = 1.
Similarly log(a/b) + log(b/a) = log (a/b * b/a);
We get log 1 bcoz all terms will get cancels
and log 1 = 0;
This is about L.H.S. So look at the R.H.S log(a+b) is there and we have to get R.H.S also zero it is possible when we get log 1 = log(a+b) so a+b = 1.
Radhe.. said:
1 decade ago
'+' indicate the multiplication in log.and '-' indicate the division in log....
Divya said:
1 decade ago
I can't understand your point. Can any one please explain me?
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers