306) PS

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by clock60 » Sat May 15, 2010 6:16 am
ern5231 wrote:a,b are negative and a ^ 2-b ^ 2> 0. Which of the following is true?

I ab> b ^ 2
II ab> 0
III ab> |ab|
i got 1 and 2
a*b>0 for sure nothing to prove
ab-b^2>0
b(a-b)>0
b<0, and as |a|>|b|, according to the problem a-b will be -ve
(-)*(-)=(+)
so to me 1 st also valid

ab>|ab| can not be valid as ab>0 and |ab|>0