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Topic: Query regarding Function
Replies: 7   Last Post: Mar 14, 2013 7:12 AM

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 Alexei Boulbitch Posts: 483 Registered: 2/28/08
Re: Query regarding Function
Posted: Mar 14, 2013 7:12 AM
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Dear all,

Case1: In the following code

Clear[f,x,y]
g=Function[{x,y},x^2+2xy][b,a]

The output is found to be b^2+2 xy

Case2: But for the code

Clear[f,x,y]
g=Function[{x,y},x^2+2y][b,a]

The output is 2 a+b^2

Hence my query is why in case 1 x*y is not replaced by b and a whereas in case 2 it got replaced ?

Regards,
rc

Hi, Rahul,

Mathematica understands xy as a single new symbol, and, therefore, it does not interpret it as a product. If you want it to be multiplication you should make a space between x and y.
Then it works. Compare: this is your function

Clear[f, x, y]
g = Function[{x, y}, x^2 + 2 xy][b, a]

b^2 + 2 xy

and this is the same, but with the space between x and y:

Clear[f, x, y]
g = Function[{x, y}, x^2 + 2 x y][b, a]

2 a b + b^2

However, I prefer to put the sign "*" between x and y. Since it becomes quite clear from the first glance, what is x*y. Like this:

Clear[f, x, y]
g = Function[{x, y}, x^2 + 2 x*y][b, a]

2 a b + b^2

Have fun, Alexei

Alexei BOULBITCH, Dr., habil.
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e-mail: alexei.boulbitch@iee.lu

Date Subject Author
3/12/13 Rahul Chakraborty
3/13/13 Peter Pein
3/13/13 Dr. Wolfgang Hintze
3/13/13 Richard Fateman
3/13/13 Frank K
3/13/13 svkeeley@aol.com
3/13/13 David Bailey
3/14/13 Alexei Boulbitch

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