help doing simple integral
08-22-2022, 09:29 PM
Post: #1
 geepigs Junior Member Posts: 10 Joined: Aug 2022
help doing simple integral
Hi, I'm having trouble doing a simple integral, the calculator keeps giving me an error.

The integral is just 0 to 1 of (X + 1) * Y^(X+1) dy, where X > -1

Any help would be appreciated.
08-23-2022, 01:14 AM
Post: #2
 Joe Horn Senior Member Posts: 2,000 Joined: Dec 2013
RE: help doing simple integral

<0|ɸ|0>
-Joe-
08-23-2022, 01:36 AM
Post: #3
 geepigs Junior Member Posts: 10 Joined: Aug 2022
RE: help doing simple integral
Thank you Joe. How were you able to add the condition that X > -1 ?
08-23-2022, 04:51 AM
Post: #4
 Joe Horn Senior Member Posts: 2,000 Joined: Dec 2013
RE: help doing simple integral
(08-23-2022 01:36 AM)geepigs Wrote:  Thank you Joe. How were you able to add the condition that X > -1 ?

The way I did it was by using the "Where" function, which looks like a long vertical line. In the math template menu (the key between the toolbox and the x-t-theta-n key), it's in the top row, 3rd item. You can see its help screen in the Toolbox Catalog menu, immediately following ztrans in alphabetical order (highlight it and press the Help key).

Another approach is to use the 'assume' command, for example:
assume(x>-1)
This tells Prime to assume that x<-1 for all future CAS work (until you change x's assumptions, or delete them, of course). I personally dislike using 'assume' because I always forget that I made assumptions and they cause me trouble later... just like in real life.

<0|ɸ|0>
-Joe-
08-23-2022, 06:36 AM (This post was last modified: 08-23-2022 06:37 AM by toml_12953.)
Post: #5
 toml_12953 Senior Member Posts: 2,094 Joined: Dec 2013
RE: help doing simple integral
(08-23-2022 04:51 AM)Joe Horn Wrote:
(08-23-2022 01:36 AM)geepigs Wrote:  Thank you Joe. How were you able to add the condition that X > -1 ?

The way I did it was by using the "Where" function, which looks like a long vertical line. In the math template menu (the key between the toolbox and the x-t-theta-n key), it's in the top row, 3rd item. You can see its help screen in the Toolbox Catalog menu, immediately following ztrans in alphabetical order (highlight it and press the Help key).

Another approach is to use the 'assume' command, for example:
assume(x>-1)
This tells Prime to assume that x<-1 for all future CAS work (until you change x's assumptions, or delete them, of course). I personally dislike using 'assume' because I always forget that I made assumptions and they cause me trouble later... just like in real life.

Before the answer shows up, I get a message saying:

Quote:No checks were made for singular points of antiderivative (x+1)*taylor8^(x+2)/(x+2) for definite integration in [0,1]

Is this supposed to happen?

Tom L
Cui bono?
08-23-2022, 07:01 AM
Post: #6
 robmio Member Posts: 170 Joined: Jan 2020
RE: help doing simple integral
(08-23-2022 06:36 AM)toml_12953 Wrote:
(08-23-2022 04:51 AM)Joe Horn Wrote:  The way I did it was by using the "Where" function, which looks like a long vertical line. In the math template menu (the key between the toolbox and the x-t-theta-n key), it's in the top row, 3rd item. You can see its help screen in the Toolbox Catalog menu, immediately following ztrans in alphabetical order (highlight it and press the Help key).

Another approach is to use the 'assume' command, for example:
assume(x>-1)
This tells Prime to assume that x<-1 for all future CAS work (until you change x's assumptions, or delete them, of course). I personally dislike using 'assume' because I always forget that I made assumptions and they cause me trouble later... just like in real life.

Before the answer shows up, I get a message saying:

Quote:No checks were made for singular points of antiderivative (x+1)*taylor8^(x+2)/(x+2) for definite integration in [0,1]

Is this supposed to happen?

Yes, this is supposed to happen
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