Aptitude - Logarithm - Discussion
Discussion Forum : Logarithm - General Questions (Q.No. 1)
1.
Which of the following statements is not correct?
Answer: Option
Explanation:
(a) Since loga a = 1, so log10 10 = 1.
(b) log (2 + 3) = log 5 and log (2 x 3) = log 6 = log 2 + log 3
log (2 + 3) 
log (2 x 3)
(c) Since loga 1 = 0, so log10 1 = 0.
(d) log (1 + 2 + 3) = log 6 = log (1 x 2 x 3) = log 1 + log 2 + log 3.
So, (b) is incorrect.
Discussion:
37 comments Page 2 of 4.
Garvit said:
10 years ago
Option D can't be considered answer. It's tricky actually:
LHS:
log (1+2+3) = log 6. [1+2+3 = 6].
RHS:
log1 + log2 + log3 = log (1x2x3) = log 6.
Since LHS = RHS (no matter how it comes) D isn't the option.
LHS:
log (1+2+3) = log 6. [1+2+3 = 6].
RHS:
log1 + log2 + log3 = log (1x2x3) = log 6.
Since LHS = RHS (no matter how it comes) D isn't the option.
Suhaas said:
9 years ago
@Palak Kapoor.
The answer is undefined.
log{5 - 4}[5^2 - 4^2 - 4]
log{1}[25 - 16 - 16]
log[25 - 32]
log[- 7]
log value for -ve is undefined.
The answer is undefined.
log{5 - 4}[5^2 - 4^2 - 4]
log{1}[25 - 16 - 16]
log[25 - 32]
log[- 7]
log value for -ve is undefined.
SYLVESTER said:
9 years ago
The given answer is absolutely correct.
Meenakshi said:
9 years ago
The anwer is absolutely correct according to log properties.
It's log a + log b = log(a * b).
not log(a + b) = log(ab).
It's log a + log b = log(a * b).
not log(a + b) = log(ab).
RAVI said:
9 years ago
@all.
B is absolutely correct.
B is absolutely correct.
Disha jhan said:
8 years ago
The answer B is correct. I agree with it.
Isaac said:
8 years ago
Can someone help me understand how D is a true statement?
If log6=10^6=1,000,000
how is that equal to log1+log2+log3?
=10^1+10^2+10^3,
=10+100+1000,
=1110.
If log6=10^6=1,000,000
how is that equal to log1+log2+log3?
=10^1+10^2+10^3,
=10+100+1000,
=1110.
Sanyal said:
8 years ago
Correct, Thanks for the given explanation.
Dhaval said:
8 years ago
D is also incorrect.
log(1+2+3) = log 1* log 2 * log 3.
log(1+2+3) = log 1* log 2 * log 3.
(1)
Riya Raj said:
7 years ago
I'm also confused because it both the cases results are coming the same soo however it's different. Please explain me.
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