document.write( "Question 228323: Please help!\r
\n" );
document.write( "\n" );
document.write( "If log b < 0, what can you say about b?\r
\n" );
document.write( "\n" );
document.write( "Thanks so much! \n" );
document.write( "
Algebra.Com's Answer #169554 by Theo(13342)![]() ![]() You can put this solution on YOUR website! Let x = a positive number.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Then -x = a negative number.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "log(b) < 0 implies that log(b) = -x because -x < 0.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now log(b) = -x if and only if 10^(-x) = b.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "This is by basic definition of logarithms.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "10^-x is the same as 1/10^x by definition.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Since x >= 0 by definition, then the smallest 10^x could be would be 1 because 10^0 = 1. \r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Any other value of x > 0 would result in 10^x being greater than 1.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Example:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "10^0.1 = 1.2589.....\r \n" ); document.write( "\n" ); document.write( "10^0.00001 = 1.0000023026\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Bottom Line is the smallest 10^x can be is 1.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now, if 1/10^x = b, this means that the largest b can be is 1 because 1/1 = 1.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "so, to answer your question:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "If log(b) < 0, this means that 0 < b < 1\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Some examples:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "log(2) = .3... \n" ); document.write( "log(1) = 0 \n" ); document.write( "log(.9) = -.04... \n" ); document.write( "log(.5) = -.301... \n" ); document.write( "log(.1) = -1 \n" ); document.write( "log(0) = Error - can only take log of a number > 0\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "So that's the answer to your question.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "log(b) < 0 if and only if b is greater than 0 and b is smaller than 1. \n" ); document.write( " |