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Peegee
02-24-2006, 01:37 AM
I really just need to know if I got the correct answer to the following:

find the limits of the following

1) lim x->∞ sqrt (4x<sup>8</sup>-10x<sup>3</sup>+x-4)
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;2x<sup>4</sup>-3x

I got '2'

2) lim x->∞ x<sup>5</sup>+8x<sup>3</sup>-4x+54
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8x<sup>5</sup>+x<sup>4</sup>-3x<sup>2</sup>-1

I got '1/8'

If you require more info please say so. Thanks! :D

-N-
02-24-2006, 01:44 AM
1 and 1/8

er yeah, AIM convo

explanation for #1:

Ignore all lower order terms. In the numerator, ignore EVERYTHING except the x^8 term, and in the denominator, ignore EVERYTHING except the x^4 term. EVERYTHING else is insignificant. Thus, you have:

sqrt(4x^8)
&nbsp;&nbsp;&nbsp;&nbsp;2x^4

Which reduces to 1.

You can do this because you're taking an infinity limit. When x gets huge, x^8 is much larger than x^3, and so on. Thus, you only consider the highest-order terms.

Peegee
02-24-2006, 01:58 AM
yep -- despite your angry outbursts I did it.

solved it to = 1 :D

ty

-N-
02-24-2006, 02:31 AM
Despite my angry outbursts?
I told you like a hundred times to check the square root of 4, man! :p

Peegee
02-24-2006, 03:07 AM
in my defence I had no idea what you were talking about :D

Doomie
02-24-2006, 03:10 AM
I'm doing Pre-Cal this year and Calculus last year so this ight help. Does sqrt mean squirt?

Peegee
02-24-2006, 11:38 AM
yep

Mo-Nercy
02-24-2006, 12:07 PM
You're supposed to be ASIAN! Why the hell would you need help in maths? :D

Rye
02-24-2006, 01:41 PM
You're supposed to be ASIAN! Why the hell would you need help in maths? :D

Damn, beat to it! :p PG, you even told me:

"I did calculus today... to see if I'm still azn..."

Shoeberto
02-24-2006, 03:25 PM
Okie dokie :)