logo

Ask Questions, Get Answers

 
X
 Search
Want to ask us a question? Click here
Browse Questions
Ad
Home  >>  JEEMAIN and AIPMT  >>  Mathematics  >>  Class11  >>  Sequence and Series
0 votes

Three positive numbers $p, q, r$ are in HP, $(r > p)$, then $log (p+r) + log (p-2q+r)$ is equal to

$(a)\;2\;log\;(r-q)\qquad(b)\;2\;log\;(p+r)\qquad(c)\;2\;log\;(r-p)\qquad(d)\;log\;pqr$

Can you answer this question?
 
 

1 Answer

0 votes
Answer : (c) $\;2\;log\;(r-p)$
Explanation : p , q , r are in HP
$q=\large\frac{2pr}{p+r}$
$=log\;(p+r)+log\;(p-2q+r)$
$=log\;(p+r)+log\;(p+r-\large\frac{4pr}{p+r})$
$=log\;(p+r)+log\;\large\frac{(p-r)^2}{p+r}$
$=2\;log\;(r-p)\;.$
answered Jan 22, 2014 by yamini.v
 

Related questions

Ask Question
student study plans
x
JEE MAIN, CBSE, NEET Mobile and Tablet App
The ultimate mobile app to help you crack your examinations
Get the Android App
...