# Entering f(x) notation in NEW CAS app

THOMAS W SEIBEL shared this question 1 year ago

In the new CAS app (Sep 4, 2019), the tutorial indicates that entering a function with f(x) notation should generate a graph in the graphics window...it does not. After the function is entered in f(x) notation the tutorial indicates that you should be able to perform various operations on the function using the function name (like evaluating the function with specific input values, taking limits of the function, derivatives, etc), but without being able to have the f(x) notation recognized by the app, these operations are not available. Am I missing something? I am able to enter a function with "y=" notation and then label the function as "f". This will generate a graph, and allow me to find the roots of the function, but none of the other function operations (Limits, Derivatives, etc).

Thanks 1

I can't check right now, but please try entering the function using :=

Like e.g. f(x):=x^2+2x+1

to see the graph and apply operations.

I can't cross check right now the Tutorial with the app. I hope that this (at least) solves your issue. 1

I’m wrong. I’ve just talked with the devs and the use of := to define a function is not wanted.

Some bugs have already been fixed for the next release. 1

So, to be clear, should I then wait for a new release for f(x) functionality? 1

Interesting fact, the := notation did generate the graph of the function. and did open up the function operations that were described in the tutorial.  2

What is the problem using the := operator? It works!

Now the CAS app can solve systems with more than three linear equations! Thanks!!

But now we miss the slider for a set of curves; a declaration like f(x)=t*x^2 is no more possible.

Any idea? 1

It doesn't work as of today. You can use

`f(x):=x^2`

to get a graph but that does not define a function. For example

```g(x):=x^2
g(4)  <-- nothing

I wanted to use it in a classroom but at the moment, the inability to define functions is a dealbreaker. Using the = operator to define a function doesn't work either. Neither a graph is plotted nor is the function object created.

You can define a function by using

```g:=x^2
```

but that workaround is crap, because of the inability to indicate the function's argument. The classic CAS handles these cases without any problems :pensive:  1

Please try v558 (iOS App only for now)