Step by step
The question
Question: find the limit as x → 0 of (x² + 2)/(x + 1).
lim x → 0 x2 + 2x + 1 =
1 Put the number in
Put 0 in place of x.
The top is 2, and the bottom is 1.
The bottom is not 0, so there is no problem here.
top: 02 + 2 = 2
bottom: 0 + 1 = 1
Careful!
L'Hôpital's rule is only for 0/0, or infinity over infinity.
Here it would give 0, which is wrong.
Careful: not L'Hôpital: f′g′ → 0 ✗
So the limit is just the value: 2.
lim x → 0 x2 + 2x + 1 = 21 = 2
2 Check
Let's check with a calculator, with x very close to 0.
x = −0.01 gives about 2.0203.
x = −0.01: x2 + 2x + 1 ≈ 2.0203
And x = 0.01 gives about 1.9803.
Both are close to 2.
Right!
x = 0.01: x2 + 2x + 1 ≈ 1.9803
Let's look back.
First: put the number in.
Last: check.
Answer
lim x → 0 x2 + 2x + 1 = 21 = 2