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NEED URGENT HELP WITH INEQUALITY PROBLEM??

Nappy · 2009-10-09 08:55:14

| x2 - 9 | < 0.01 (a) Solve the inequality (b) Use your answer to find a positive number a such that | x - 3 | < a => | x2 - 9 | < 0.01 I can get the first bit, solutions for x are sqrt( 8.99) < x < sqrt ( 9.01 ) but im not sure where to start with second?? Any help would be much appreciated.. Cheers..

09-10-2009 8:55am

#1

Nappy

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| x2 - 9 | < 0.01

(a) Solve the inequality

(b) Use your answer to find a positive number a such that

| x - 3 | < a => | x2 - 9 | < 0.01

I can get the first bit, solutions for x are sqrt( 8.99) < x < sqrt ( 9.01 ) but im not sure where to start with second?? Any help would be much appreciated..

Cheers..

0

Comments

#2 09-10-2009 9:53am

LeixlipRed

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Posts: 5982

Factorise [latex]x^2 - 9[/latex] and what do you get?

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