@Soumyabrata Mondal
Even I had thought of that before.
But you see,
\dpi{200} \fn_cs e^{i\pi} = -1\Rightarrow log(-1) = i\pi
Hence log(-1) does have a value.
Soumyabrata Mondal i(pi) is nt real. i is an imaginary number.
Shaswata Roy Doesn't matter if it is not real...as long as it is some value which can be cancelled from both the sides.
Shaswata Roy Actually I had seen this on a post given by a Singaporean olympiad trainer.He said that log of a negative no. can be taken.
Shaswata Roy All I know is that the answer has got something to do with the property of log (or antilog don't know,:P) and it has got something to do with one to one correspondence or something like that.
Soumyabrata Mondal ok, then I think it is out of my knowledge :-(