Is f(x)δ(x) Equal to f(2)δ(x)?

athrun200 · Jul 22, 2011

Homework Statement

Can I write, say, [itex]f(x) \delta(x)=f(2)\delta(x)[/itex]?
Since [itex]\delta(x)[/itex] =0 for x[itex]\neq[/itex]0

hunt_mat · Jul 22, 2011

I think you can say [itex]f(x)\delta (x-2)=f(2)\delta (x)[/itex]

athrun200 · Jul 22, 2011

hunt_mat said:

I think you can say [itex]f(x)\delta (x-2)=f(2)\delta (x)[/itex]

Then if x=2, left hand side will become infinity and the right hand side 0.
Is it Ok?

athrun200 · Jul 22, 2011

So what's wrong with my post in #1?

Dick · Jul 22, 2011

athrun200 said:

So what's wrong with my post in #1?

The integral of [itex]f(x) \delta(x)[/itex] over x is f(0). The integral of [itex]f(2) \delta(x)[/itex] over x is f(2). So no, they aren't the same.