Question 1028423: I'm not sure if this is the right place for this question, but it seemed the most appropriate.
What is the limit of 2(x^2)(e^x) as x approaches negative infinity.
Technically this is a calculus question, but what I'm more interested in is how to manipulate the given equation. Apparently, (x^2)(e^x) can be rewritten as (x^2)/(e^(-x)). I understand the use of reciprocals and conjugates, but how can someone just flip one part of the equation like that?
Answer by fractalier(6550)   (Show Source):
You can put this solution on YOUR website! What we consider in questions like this is the rate of growth (or decay) between the functions in question.
In this particular case, we understand that exponentials grow (or decay) faster than powers...
Thus this expression goes to zero as x moves toward negative infinity...
What you can do is plug in, say, x = -50, and you'll see how small it gets...
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