. Have a doubt in LOGARITHM!!!!!! IT is said that as we cannot express ZERO and NEGATIVE NUMBERS as a power of a positive number,the logarithms of zero and negative numbers are not defined.WHY IS IT SO?can u give an example???AM VERY CONFUSED....

Asked by Anagha P | 6th Apr, 2011, 12:00: AM

Expert Answer:

Dear student
Your question is:
Why log is not defined for negative numbers?
Ans. By the def. of log:   .
take an example:
if x = 3 and a = 2, then y = 32 = 9
if x = 3 and a = -2, then y = 3-2 = 1/9
if x = -3 and a = 2, then y = (-3)2  = 9
if x = -3 and a = -2, then y = (-3)-2  = 1/9
Thus if x and a are +ve or -ve, y is always positive.
therefore y can not be negative in any case and so log for negative number is not defined. 
Remark: Log of negative numbers are defined in term of complex number which is not included in course.
Hope it resolve your quarry.
Team Topper

Answered by  | 6th Apr, 2011, 09:46: AM

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