elitmus
Exam
Numerical Ability
Log and Antilog
what is the minimum value of f(x) where
f(x)=(logax+logbx+logcx) and a>b>c>1..
option
a. 3
b 2
c 1
d 4
Read Solution (Total 5)
-
- here a,b,c are base for log..they aren't multiplied with x.
so logax=logex/logea;
f(x)= (logx/loga + logx/logb+ logx/logc);
= logx * (1/loga + 1/logb + 1/logc);
for minimum value of f(x) log values must me max 1
=1*3
= 3 - 8 years agoHelpfull: Yes(11) No(2)
- a it can be written as log x(1/log a + 1/log b + 1/ log c) log a ,b,c can be max 1 at that point fx is min so answer is 3
- 8 years agoHelpfull: Yes(3) No(4)
- but here given that c>1 and a>b>c so how can it be possible to take 1/loga=1/logb=1/logc=1
- 8 years agoHelpfull: Yes(2) No(1)
- if we take x=1 then f(x) is becoming 0.
please rectify if i am wrong. - 8 years agoHelpfull: Yes(0) No(1)
- And after adding these three values, when we multiply it with log x; then what will be the minimum answer (-:
- 7 years agoHelpfull: Yes(0) No(0)
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