InterviewSolution
Saved Bookmarks
InterviewSolution
| 1. |
If `log_(2)(5.2^(x)+1),log_(4)(2^(1-x)+1)` and 1 are in A.P,then x equalsA. `log_(2)5`B. `1- log_5 2`C. `log_(5)2`D. `1-log_(2)5` |
|
Answer» Correct Answer - D The given numbers are in A.P. Therefore, `2log_(4)(2^(1-x)+1)=log_(2)(5xx2^(x)+1)+1` or `2log_(2^(2))(2/(2^(x))+1)=log_(2)(5xx2^(x)+1)+log_(2)2` or `2/2loglog_(2)(2/(2^(x))+1)=log_(2)(10xx2^(x)+2)` or `2/(2^(x))+1=10xx2^(x)+2` `rArr2/y+1=10y+2`, where `2^(x)=y` or `10y^(2)+y-2=0` or `(5y-2)(2y+1)=0` `rArry=2//5` or `y=-1//2` `rArr2^(x)=2//5` or `2^(x)=-1//2` `rArr x=log_(2)2-log_(2)5` `[because2^(x)` cannot be negative`]` `rArrx=log_(2)2-log_(2)5` `rArrx=1-log_(2)5` |
|