I recently had this of a midterm f(x) = 2^-x f''(x) = ? I know that d(2^x)/dx = ln2*2^x but that formula didn''t seem to work for 2^-x when I ran my programs on it. If you could replace that question mark, it would put me at ease.

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There is no topic so thoroughly covered that noone will ever bring it up again.

This isn't so much a formula that you can substitute -x for x. You need to use the chain rule to get (2^-x)' = -ln2*2^-x.

You might have done this, but I can't tell from your post

Edited by - sQuid on February 26, 2002 6:49:34 PM

Set y = -x, f(y) = 2^y
f''(y)_x = d(2^y)/dy * dy/dx

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Thanks to Kylotan for the idea!

That was fast. Thanks guys.

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There is no topic so thoroughly covered that noone will ever bring it up again.

This short topic is okay, but please remember to keep discussions on the topic of game development.

Graham Rhodes
Senior Scientist
Applied Research Associates, Inc.