Advertisements

Tuesday, April 26, 2016

Logarithms–Important Laws & Formulas


Q) Why log 1=0?
The important thing to remember is the log represents the exponent.  In the case of common logs, the base is always base 10.  Now lets see some examples which clears your doubt:
1) log 100 = 2 because 102 = 100.
2) log 1000 = 3 because 103 = 1000.
3) log 1 = 0 because 100 = 1.
4)  log .1 = -1 because 10-1 = .1
5)  log .01 = -2 because 10-2 = .01logarithms important formulaes for SSC
Q) How to change base in logarithms?
We can change any base to a different base any time we want. The most used bases are obviously base 10 and base e.
Change of base formula:  Logb x = Loga x/Loga b

Q) Some Important Laws/Formulas in Logarithms:
1)  Logb MN = Logb M + Logb N
2)  Logb M/N = Logb M - Logb N
3)  Logb M = Logb N if and only if M = N
4)  Logb Mk = k Logb M
5)  Logb b = 1
6)  Logb 1 = 0
7)  Logb bk = k
8) bLogb x = x
Note: Post a question in comments, we will reach you providing solutions.

No comments:

Post a Comment