a>1,Divergent,a<or=1,limit is 1.You can try in your calculator for a=.1,several times later,you'll get .999...
Another Q maybe ...for you :
X=2+(2+(2+(2+....)^.5)^.5)^.5)^.5
We can use X=(2+X)^.5,...We get X=2. ...2 can change to a,...X=(a+X)^.5,...
Happy Holidays.