       Re: How if I want to assume that -------

• To: mathgroup at smc.vnet.net
• Subject: [mg64579] Re: [mg64550] How if I want to assume that -------
• From: Bob Hanlon <hanlonr at cox.net>
• Date: Thu, 23 Feb 2006 00:34:13 -0500 (EST)
• Sender: owner-wri-mathgroup at wolfram.com

```Integrate[1/(x-y),{x,0,5}]

If[Re[y] >= 5 || Re[y] <= 0 || Im[y] != 0, Log[5 - y] - Log[-y], Integrate[1/(x -
y), {x, 0, 5},
Assumptions ->  !(Re[y] >= 5 || Re[y] <= 0 || Im[y] != 0)]]

Simplify[%,{x>y,y>5}]

Log[(y - 5)/y]

Integrate[1/(x-y),{x,0,5},Assumptions->{x>y,y>5}]

Log[(y - 5)/y]

Assuming[{x>y,y>5},Integrate[1/(y-x),{x,0,5}]]

Log[y/(y - 5)]

Bob Hanlon

>
> From: kong dong <dkong at lnm.imech.ac.cn>
To: mathgroup at smc.vnet.net
> Subject: [mg64579] [mg64550] How if I want to assume that -------
>
> Thank you for your attention,
>
> Does there exist a 'assume' function in Mathematica?
> For example, I want to assume that
>         { x>y }
>
> Thank you!
>
>

```

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