[igraph] fitting a straight line to power-law distribution

[Narges Zarrabi]

Hi,

I am trying to understand the fitting to the power law distribution in the example in link below:

http://igraph.sourceforge.net/screenshots2.html#8

However, in the following line of the example:

lines(10:500, 10*(10:500)^(-coef(alpha)+1))

I don't understand why +1 is added in the power (-coef(alpha)+1)

Could anyone explain the reason ? Thanks

Regards,

Narcis