I wanted to graph gamma function (integral from 0 to infinity, but 0 to 100 is still accurate, of t^(X-1)*e^-t dt), but i cannot do 'dt', only 'dx', and when I use dx, the program do not know what is the part of integral, and what is the argument of function.

# Graph of Integral

### #1

Posted 16 January 2018 - 04:23 PM

### #2

Posted 16 January 2018 - 07:06 PM

You have to use x for the integration variable and rewrite the function in x: x^(Z-1)*e^-x dx

### #3

Posted 17 January 2018 - 08:09 AM

You have to use x for the integration variable and rewrite the function in x: x^(Z-1)*e^-x dx

Z is treated as a variable, not as an argument of a function. Is there a way to set up Z as an argument?

### #4

Posted 17 January 2018 - 01:28 PM

You cannot have x AND z als Argument.

### #5

Posted 17 January 2018 - 05:58 PM

You cannot have x AND z als Argument.

So what do i have to do to set only Z as an argument, so it no longer will be treated as a number (stored in variable Z)

So what do i have to do to set only Z as an argument, so it no longer will be treated as a number (stored in variable Z)

### #6

Posted 17 January 2018 - 06:47 PM

I don't know whether we speak about the same thing, but I wrote a program for calculation of the gamma function

Goto I Lbl A ?->Z 0->S:1->P For 0->N To 6 S+List 1[N+1]Z^N->S P(Z+N)->P Next (S/P)((Z+5.5)^(Z+.5)e^(-(Z+5.5)) Stop Lbl I 7->Dim List 1 75122.6331530->List 1[1] 80916.6278952->List 1[2] 36308.2951477->List 1[3] 8687.24529705->List 1[4] 1168.92649479->List 1[5] 83.8676043424->List 1[6] 2.50662827511->List 1[7] Goto A

### #7

Posted 18 January 2018 - 07:58 AM

The integral gives you a result for a single value of z. If you want to have a graph of all z, you need to solve the integral for every z independently. Or you use the approach I gave.

### #8

Posted 18 January 2018 - 11:41 AM

I compared my program with the implemented intergal function. Some examples:

My program :

Z=0.5 G(Z)=1.772453851

Z=2.7 G(Z)=1.544685846

Z=4.1 G(Z)= 6.812622863

In Math Mode

999 ´ | Z-1 -X | X e dx | , 0

0.5 G(Z)=1.772453679 (runs around 5 seconds)

2.7 G(Z)=1.544685843

4.1 G(Z)=6.812622865

### #9

Posted 18 January 2018 - 10:34 PM

### #10

Posted 19 January 2018 - 05:04 AM

No way. You may use my litttle program, make loop in Z around it end a plot line in it.

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