1 Topic by m255173 (edited by m255173 2012-09-08 04:23:05)

Topic: Where & How do I specify a Special Function: Integrate ?

Graph is a wonderful program.

Question:
---------

I have graphed a std. function:
   y = 1800-2x   
with "x" btw. values:  0 to 500.
OK!

I then clicked the Area button (@ top).
The Area under my graph,
with "x" btw. values:  0 to 500
is returned:  650,000.
Excellent!

But now,
I'd like to add and display
another function to the graph,
corresponding to the *** Integral ***
of my std. function:  (y = 1800-2x).

The Doc Help file of Graph,
mentions a Special Function called "Integrate".
I imagine the syntax in my case would be:
    f(x)=integrate(1800-2x, x, 0, 500).

a)   Is the above Integrate expression correct ?
b)  Where in the Graph program
     do I enter the above expression, with the Special Function "Integrate"?

I must be missing something basic...
Tak / Thanks for any help!

Re: Where & How do I specify a Special Function: Integrate ?

f(x)=integrate(1800-2x, x, 0, 500) will plot the definite integral of f(x)=1800-2x from 0 to 500. You enter it in the Insert function dialog as any other function. However this will just plot a line at y=650000.

What you want is probably the indefinite integral. To plot that, you enter the function f(x)=integrate(1800-2s, s, 0, x)

3 Reply by m255173 (edited by m255173 2012-09-09 04:58:33)

Re: Where & How do I specify a Special Function: Integrate ?

Perfect...
Tusend Tak!!   smile

A suggestion for a future version:

Given (for ex.),
       f(x) = 1800-2x    btw x=0 and x=500,

include in top menu an
       [ Integrate Button ],
for prog. to show the User
that the Integral of above f(x) is:
             = 1800x - x^2   
and has a value of:
             = 650,000   when eval on dx, from x=0 to x=500 .

This is similar to what the prog. already does ,
i.e.  it shows the User
the Derivatives f' and f"  for a given  f(x).

Hope this makes sense.

Thanks again Ivan!
SF99

Re: Where & How do I specify a Special Function: Integrate ?

That would be a great feature. Unfortunately symbolic integrations is a lot more difficult than symbolic differentiation.

5 Reply by m255173 (edited by m255173 2012-09-09 22:15:31)

Re: Where & How do I specify a Special Function: Integrate ?

Yes, I understand.

Anyhow, Ivan - thanks for Graph.
It is truly a great program...

Have a nice weekend!
SF99