View Full Version : mathematics polynomial long division

xddxogm3

11-07-2004, 11:23 PM

I think I found an error in my math book.

I'm using polynomial long division to calculate the slant asymptote. can someone check this to see if i'm correct.

the book says the following.

(x^2-4x-5)/(x-3)=x-1+(8/x-3)

I think it should be

(x^2-4x-5)/(x-3)=x-1-(8/x-3)

note the only difference is the subtraction/addition of the remainder fractional value.

who is correct? (me or book)

laserlight

11-08-2004, 04:53 AM

The simplest way to check is to plugin values.

Let's try x=7

(x^2-4x-5)/(x-3) = 16/4 = 4

x-1+(8/(x-3)) = 8

x-1-(8/(x-3)) = 4

The book must be wrong, while you are probably correct.

chrismiceli

11-08-2004, 07:46 AM

I am not in the highest forms of math, but for polynomial division, isn't there something called synthetic division: http://www.purplemath.com/modules/synthdiv.htm . I don't know if that is what you want to use or if you are even allowed, but if you want to expand your math concepts, look into it.

xddxogm3

11-08-2004, 08:32 AM

yes, i know about synthetic division.

i was almost certain i was correct, but wanted to make sure, that i was not making a mistake somewhere, with forgeting some obscure special case rule.

this book i'm using is horrible. it doesn't have all the answers, and some of the text has been proven to be inaccurate.

thank you both

Perspective

11-08-2004, 10:33 AM

I think some high school math/sci books intentionally give false answers to every nth numeric answer. It makes it easier for the teacher to see if someone is using the back of the book a little too much ;)

xddxogm3

11-08-2004, 05:29 PM

the error was in the actual lesson walk through.

so it was teaching me the wrong way.

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