       Re: conditional limits

• To: mathgroup at yoda.physics.unc.edu
• Subject: Re: conditional limits
• From: belopols at marie.mit.edu (Alexander Belopolsky)
• Date: Tue, 7 Sep 1993 14:28:58 -0400

```>   I have a function of two variables, f[x, y], which when evaluated for values of
>   x=y results in:
>						  1
>		 Power::infy: Infinite expression -- encountered.
>						  0.
>
>   As there is an (x-y) term in the denominator of the function.  However,
>   the Limit[f[x,y], x-y] does exist, and evaluates to a finite number.
>
>
>   The question is, how do I construct a rule that conditionally evaluates
>   the limit of f[x,y] rather than f[x,y] whenever x=y?

Here is my solution:
In:= f[x_,y_]:=Sin[x-y]/(x-y)

In:= f[3,3]

1
Power::infy: Infinite expression - encountered.
0

Infinity::indet: Indeterminate expression 0 ComplexInfinity encountered.

Out= Indeterminate

In:= f[x_,x_]:=Limit[f[x,y],y->x]

In:= f[3,3]

Out= 1

```

• Prev by Date: FindMinimum
• Next by Date: Re: plotting graphs with asymptotes
• Previous by thread: conditional limits
• Next by thread: Re: conditional limits