I'll recall another section
what is a power of a^0 ?
By definition, a^n=a*a*...a (n factors)
we can't find out what a^0 means
but a^0=1 works (if, for example, we think of (a^7)/(a^7)=1)
So we DEFINE a^0=1
The same as 0! (factorial) - we define it although there is not a...