+0

# How do you solve this?

0
47
2

$$limit( x^3*e^x, x=-inf )$$

also this

$$limit( (x^3+2x)*(cos(3/x^2))), x=0 )$$

Guest Apr 13, 2018

#1
+26634
+2

When x is negative ex goes to zero much faster than x3 goes to -infinity, so:   $$\lim_{x\rightarrow -\infty}(x^3e^x)=0$$

The value of cosine is always bounded such that it's magnitude is never greater than 1.

Hence:   $$\lim_{x\rightarrow 0}((x^3+2x)\cos(3/x^2))=0$$

.

Alan  Apr 13, 2018
Sort:

#1
+26634
+2

When x is negative ex goes to zero much faster than x3 goes to -infinity, so:   $$\lim_{x\rightarrow -\infty}(x^3e^x)=0$$

The value of cosine is always bounded such that it's magnitude is never greater than 1.

Hence:   $$\lim_{x\rightarrow 0}((x^3+2x)\cos(3/x^2))=0$$

.

Alan  Apr 13, 2018
#2
0

I see, thank you very much

Guest Apr 15, 2018

### 33 Online Users

We use cookies to personalise content and ads, to provide social media features and to analyse our traffic. We also share information about your use of our site with our social media, advertising and analytics partners.  See details