sean doyle

2008-02-05 13:49:54 UTC

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x, can anyone help?

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sean doyle

2008-02-05 13:49:54 UTC

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x, can anyone help?

Virgil

2008-02-05 18:20:26 UTC

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Tried without success to differentiate 1/x from first principles using delta

x, can anyone help?

[1/(x+h) - 1/x]/h = [(x - (h+h))/(x*(x+h))]/h

= [-h/(x*(x+h)]/h

= -1/(x*(x+h))

--> -1/x^2 as h --> 0

Ken Pledger

2008-02-06 23:47:17 UTC

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....

[1/(x+h) - 1/x]/h = [(x - (h+h))/(x*(x+h))]/h ....

Just in case it confused the OP, I'll mention the typo:[1/(x+h) - 1/x]/h = [(x - (h+h))/(x*(x+h))]/h ....

(x - (h+h)) should have been (x - (x+h)).

Ken Pledger.

Virgil

2008-02-07 01:16:16 UTC

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....

[1/(x+h) - 1/x]/h = [(x - (h+h))/(x*(x+h))]/h ....

(x - (h+h)) should have been (x - (x+h)).[1/(x+h) - 1/x]/h = [(x - (h+h))/(x*(x+h))]/h ....

Ken Pledger.

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