Let (an) be a sequence of positive real numbers 1 2 such that lim - a ...
The given sequence:
Let (an) be a sequence of positive real numbers such that:
limn→∞ -an = -8
Finding the limit:
We are asked to find the value of:
limn→∞ an + 4
Since the limit of -an is -8, we can rewrite it as:
limn→∞ (-an) = -8
Using the properties of limits:
We know that if limn→∞ f(n) = L, then limn→∞ (-f(n)) = -L.
Using this property, we can rewrite the given limit as:
limn→∞ (-an) = -(-8) = 8
Applying limit rules:
Next, we can use the property that if limn→∞ f(n) = L, then limn→∞ [f(n) + c] = L + c, where c is a constant.
Applying this property to our limit, we have:
limn→∞ [(-an) + 4] = 8 + 4 = 12
Final result:
Therefore, the value of limn→∞ an + 4 is equal to 12.
In summary:
- The given sequence is (an).
- The limit of -an is -8.
- Using the properties of limits, we find that the limit of an is 8.
- Applying the limit rules, we find that the limit of an + 4 is 12.