# Math Help - Limit Comparison Test

1. ## Limit Comparison Test

This seems like a fairly easy problem, but i'm not getting the book's answer.

The sum from x=1 to infinity of 2x^2-1/3x^5+2x+1

The book seems to expunge enough to make a reference series 1/x^3, which is a p-series. I just don't see how you can expunge that much..

The question is as written in the book and asks: Use the Limit Comp. Test to determine the convergence or divergence of the series. No parenthesis are needed. the ^ implies something raised to a power.

2. Originally Posted by bakeit1
This seems like a fairly easy problem, but i'm not getting the book's answer.

The sum from x=1 to infinity of 2x^2-1/3x^5+2x+1

The book seems to expunge enough to make a reference series 1/x^3, which is a p-series. I just don't see how you can expunge that much..
Can you group some things with parenthesis to make it a little more clear as to what the question is.
Thank you!

3. Originally Posted by bakeit1
This seems like a fairly easy problem, but i'm not getting the book's answer.

The sum from x=1 to infinity of 2x^2-1/3x^5+2x+1

The book seems to expunge enough to make a reference series 1/x^3, which is a p-series. I just don't see how you can expunge that much..

The question is as written in the book and asks: Use the Limit Comp. Test to determine the convergence or divergence of the series. No parenthesis are needed. the ^ implies something raised to a power.
Hello,

The parenthesis were for (2x^2-1)/(3x^5+2x+1) because it could be interpreted as 2x^2-(1/(3x^5+2x+1)) for example.

For the p-series : divide the numerator & the denominator by x^2.
Then, observe...

4. Originally Posted by Moo
Hello,

The parenthesis were for (2x^2-1)/(3x^5+2x+1) because it could be interpreted as 2x^2-(1/(3x^5+2x+1)) for example.
Thank you Moo...

And...

sometimes people don't put in parenthesis when they need to..they just leave them out...I'm a big fan of grouping symbols anyway. Just my little OCD I suppose.