tarunlakhani Posted September 20, 2011 Share Posted September 20, 2011 Hi! I came across this - "The square root of a negative number is not a real number." I used to think that all numbers are real number (Positive/Negative/Rational/Irrational/Integer):confused: Requesting the members to respond with lucid explanation if possible. Also, it would be great if someone can forward a link that lists Number Properties. Thanks TARUN Quote Link to comment Share on other sites More sharing options...
Brent Hanneson Posted September 20, 2011 Share Posted September 20, 2011 This is true: the square root of a negative number is not a real number. The square root of a negative number is called a complex number (it's also referred to as an imaginary number) On the GMAT, we are told to limit our mathematics to real number. So, for example, if we are told to solve x^2 = -4 for x, we know that x = root(-4) or x = -root(-4). Since root(-4) is not a rel number, we say (when taking the GMAT) that this equation has no solution. As far as a list of Number Properties goes, the Official Guide explains everything you need to know. Cheers, Brent Online video lessons | GMAT Prep Now Quote Link to comment Share on other sites More sharing options...
tarunlakhani Posted September 20, 2011 Author Share Posted September 20, 2011 Thanks Brent. Is there a strategy to solve number property questions? While reading the properties, they seem easy and doable. However, wen framed in ques they seem so highly confusing. Quote Link to comment Share on other sites More sharing options...
tarunlakhani Posted September 20, 2011 Author Share Posted September 20, 2011 On similar lines, I find that x^2 +5=0 has no solution. Since, x^2 + 5 is always greater than 1. Thanks Brent Quote Link to comment Share on other sites More sharing options...
Brent Hanneson Posted September 21, 2011 Share Posted September 21, 2011 Thanks Brent. Is there a strategy to solve number property questions? While reading the properties, they seem easy and doable. However, wen framed in ques they seem so highly confusing. That's a very open-ended question with no easy answer. That said, I feel that many number (integer) properties questions can be solved using prime factorization. Cheers, Brent Online video lessons | GMAT Prep Now Quote Link to comment Share on other sites More sharing options...
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