How to use the square difference formula to calculate the square of 2006-2007*2005

How to use the square difference formula to calculate the square of 2006-2007*2005

Square of 2006-2007*2005
=2006^2-(2006+1)(2006-1)
=2006^2-(2006^2-1)
=1

(-3) Multiplied by one-third of the 2006 power

(-3)^2005*(1/3)^2006
=-1/3