正確說無所謂的收斂..而是發散與非發散..因為有些函數的極限值會在兩點間跳來跳去
f(n)=(7^n)-1 or f(n)=7^(n-1) 這兩個都是發散

贊助商連結

grr... 收斂因是when your factor(like in here is n) to +oo or -oo, the value of equation would close to constant.. like 1, 8 or 100..

what i know is that f(n)=7^n-1 is 發散