# Improper Integral

#### Kcashew

##### New member
Good morning everyone.

I hope I can get some help on this problem.

I believe I have taken the integral correctly, but I do not know how to implement infinity into it.

How should I go about solving this?

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#### pka

##### Elite Member
What is the limit as $$b\to\infty~?$$

#### Kcashew

##### New member
Yes, that is correct

#### Kcashew

##### New member
What is the limit as $$b\to\infty~?$$

What I meant to say was, I do not know how to compute that.

#### Jomo

##### Elite Member
Please write down the limit you are having trouble with, so everyone is on the same page, state why you are having trouble and you will be expertly helped. Fair enough?

#### pka

##### Elite Member
WAIT SORRY I misread that What I meant to say was, I do not know how to compute that.
$$\displaystyle\left. { - {e^{ - x}}(x + 1)} \right|_0^b = \left[ { - {e^{ - b}}(b + 1)} \right] - \left[ { - 1(1)} \right]$$
Now what is the limit as $$b\to\infty$$

#### Kcashew

##### New member
Please write down the limit you are having trouble with, so everyone is on the same page, state why you are having trouble and you will be expertly helped. Fair enough?
This was what I was having trouble with

$$\displaystyle\left. { - {e^{ - x}}(x + 1)} \right|_0^b = \left[ { - {e^{ - b}}(b + 1)} \right] - \left[ { - 1(1)} \right]$$
Now what is the limit as $$b\to\infty$$

#### Kcashew

##### New member
I believe that the limit would be 1, considering that E is raised to the power of negative infinity

#### pka

##### Elite Member
I believe that the limit would be 1, considering that E is raised to the power of negative infinity
CORRECT