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bit of proof, help

Please help with the following question.

Show that if ax<<1\frac{a}{x}<<1 then 1x−1x+a\frac{1}{x}-\frac{1}{x+a}≈ax2\frac{a}{x^2}

thanks
Reply 1
Avatar for nuodai
nuodai
17
Combine the fractions. What do you notice?
Reply 2
Avatar for Tim_Lehner
Tim_Lehner
OP
Original post by nuodai
Combine the fractions. What do you notice?



If I do that I get ax(a+x)\frac{a}{x(a+x)}
but how do I get from that to ax2\frac{a}{x^2}
what is significant about ax<<1\frac{a}{x}<<1
(edited 12 years ago)
Reply 3
Avatar for gff
gff
5
Something is a lot less than something else. What does this ratio tell you about aa compared to xx?
Reply 4
Avatar for Tim_Lehner
Tim_Lehner
OP
ahh I'm such a moron, got it, thanks haha

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