# Calculate derivatives on Casio Graphics Calculator?

Is there any way I can calculate derivatives using a Casio Graphing Calculator?

Is there a program available for the calculator which can calculate them?

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What specific model of Casio graphing calculator? –  Isaac Mar 13 '11 at 4:21
Casio CFX-9850GC Plus –  MathsStudent Mar 13 '11 at 7:04

## 1 Answer

I don't have that model at hand to check for sure, but I think you can get a numerical approximation of the derivative at a point by graphing the function and using the trace feature with derivative turned on in the settings. Here is the relevant section of the manual, from chapter 8:

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Thanks! I can find the numerical value of the derivative using that function, but what I really need is the actual function itself. Is there any way I can (quickly) work backwards from the numerical value to confirm the derivative I have calculated manually is correct? –  MathsStudent Mar 13 '11 at 7:40
@user8176: I'm pretty sure that your model of Casio won't give you a formula for the derivative. The best you could do is probably to get several numerical approximations of the derivative and note the pairs $(x,f'(x))$ from the calculator, then try those values of $x$ in the formula you think is the derivative to see if the values match. If the values don't match, your formula is probably wrong; if the values do match, it's not a guarantee your formula is right, but it is a quick check. –  Isaac Mar 13 '11 at 7:44