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Re: Limits

atse1900 said:
lim (radical(9x^2+x)-3x)
x->infinity
Click to expand...
I may hurt your feelings on this one. I'm going to ask you to UNrationalize the denominator. Have you ever done that on purpose?

Multiply Numerator (radical(9x^2+x)-3x) and Denominator (1) separately by:

radical(9x^2+x) + 3x <== Note the "plus" in the middle. Sort of a conjugate.
 
So very close :!:
Look at the sign of the three in the denominator.
PS: Then move the /x under the radical.
 
So very close :!:
Look at the sign of the three in the denominator.
PS: Then move the /x under the radical.
Click to expand...

I am really stuck there. LOL. That's why I am asking where to go next....
 
You'll blush. Oh well...
You multiplied the numerator by
radical(9x^2+x)+3x
You have to multiply the denominator by the same thing so you should get
x/(radical(9x^2+x) + 3x)
With that change your steps take you to
1/(radical(9x^2+x))x + 3)
When you move the x under it you have
1/(radical(9x^2+x)/x²) + 3)
I'll let you try again from there.
 
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