The numerator in your expression starts with two spaces. That is the source of the invisible parameter:

Try to rewrite the expression:

Please make one more post describing simply and clearly what you want the notebook to accomplish.

Just before you click "Publish" to send the post click "Add a file to this post" and locate your notebook which demonstrates as simply as possible the problem you are having and select that notebook so it will be attached to your message. Then click "Publish."

Hopefully this will avoid problems of the forum software making changes to what you are writing and will allow readers to download the exact notebook you have, run it, determine the problem and explain how to avoid this problem.

Hello,

Thank you for your answer. But in fact, this ".1d" showed up only when I coped and pasted here. In the mathematica file, I dont see it, thats why I say it is an invisible parameter. See the PFD I attached to the first post, mathematica graphs the number, as if there was some parameter, although I can't see it.

So on my file when I click on plot I see something like:

Manipulate[ Plot[ 1/2 (-1 + k)^ L k^(-2 L) , {k, 1, 20}], {, 1,20}, {L, -2, 2}, {V, -2, 2}]

I don't know why this {, 1,20} shows up, and if I remove it the graph doesn't display.