Aptitude - Logarithm - Discussion

Discussion Forum : Logarithm - General Questions (Q.No. 1)
1.
Which of the following statements is not correct?
log10 10 = 1
log (2 + 3) = log (2 x 3)
log10 1 = 0
log (1 + 2 + 3) = log 1 + log 2 + log 3
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 4 of 4.

Murali said:   1 decade ago
243 base 9.

This mainly 243 = 3*3*3*3*3 = 3^5.

And 9 = 3*3 = 3^2.

So answer is 5/2. I dot no how to write log in keyboard.

Akshayaa said:   1 decade ago
What about 828 with base 2?

Tendai said:   1 decade ago
What about 243 base 9?

Vikash said:   1 decade ago
log 6 = log(2*3) = log 2 + log 3.

But log(2+3) =log 5 which is not equal to log 6.
So, log(2+3) != log 2 + log 3.
(1)

Venu said:   1 decade ago
If they say log 6 = log 2 + log 3, then log (2+3) = log 2 + log 3.

Can someone explain ?

Begum said:   1 decade ago
Its great.

K.manohar reddy said:   1 decade ago
Its absolutely correct.


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