(TI-36X Pro) Using f(x) in Calculus
03-14-2020, 02:31 PM
Post: #1
 Eddie W. Shore Senior Member Posts: 1,491 Joined: Dec 2013
(TI-36X Pro) Using f(x) in Calculus
You use the function stored in the table function f(x) in calculus functions: evaluation, numeric derivative, definite integrals

03-14-2020, 11:50 PM
Post: #2
 lrdheat Senior Member Posts: 810 Joined: Feb 2014
RE: (TI-36X Pro) Using f(x) in Calculus
You can define g(x) in table to equal d/dx f(x), and then solve g(x)=0 in numerical solve to find an extremum. In the home screen, you can then call up f(x) to find the extremum value at x.
03-15-2020, 07:28 AM (This post was last modified: 03-15-2020 07:53 AM by Csaba Tizedes.)
Post: #3
 Csaba Tizedes Senior Member Posts: 591 Joined: May 2014
RE: (TI-36X Pro) Using f(x) in Calculus
(03-14-2020 11:50 PM)lrdheat Wrote:  You can define g(x) in table to equal d/dx f(x), and then solve g(x)=0 in numerical solve to find an extremum. In the home screen, you can then call up f(x) to find the extremum value at x.

Unfortunately this works ONLY on the new model, because on the TI-36X Pro only f() is available. But, on the new model, when you defined g(x) as d/dx(f(x)), you can run numeric solver and you can solve numerically the following equation:

(g(x+a)-g(x-a))/(2a)=0

And you can find the inflection points, where the second derivative is zero.
You can do the same on the older model, if you defined f() as the derivative of your function.

On the older and new model, with the numerical solver you can solve first order ODEs easily, you must to separate the diffeq and write the left and right side integration into numerical solver, like on this CASIO video:

For information, the NEW model on the middle and the OLD model on the right.
The new model more-more-more capable than the old - but this is manufactured only for the European market, no US version available and sold only in European countries. Csaba
03-15-2020, 02:43 PM
Post: #4
 lrdheat Senior Member Posts: 810 Joined: Feb 2014
RE: (TI-36X Pro) Using f(x) in Calculus
That is true...but on the 36X, if f( is defined as d/dx of the function of interest, and is solved in number solve to equal zero, the result is the x value of the extremum. You can then bring up edit f(, and delete the “d/dx” part, quit, hit table, bring up f(, and make it f(x), enter, and you get your f(x) value for the x value for your extremum point.
03-15-2020, 06:15 PM
Post: #5
 Csaba Tizedes Senior Member Posts: 591 Joined: May 2014
RE: (TI-36X Pro) Using f(x) in Calculus
(03-15-2020 02:43 PM)lrdheat Wrote:  That is true...but on the 36X, if f( is defined as d/dx of the function of interest, and is solved in number solve to equal zero, the result is the x value of the extremum. You can then bring up edit f(, and delete the “d/dx” part, quit, hit table, bring up f(, and make it f(x), enter, and you get your f(x) value for the x value for your extremum point.

As I wrote: "You can do the same on the older model, if you defined f() as the derivative of your function."

My colleagues do not like my work-emails, because its length (too long).

My message above was four line + one video + one picture. What is the max length on MoHPC it can read by an average user and can understand?!?

But, yes, you can do it on the older model, as WE wrote TOGETHER.

This is really a good calculator, it is possible to solve many basic calculus problem with it. Here a volume calculation: Volume of e^(-x^2) Cs.
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