polynomial division and remainder theorem

• Jul 30th 2012, 10:22 AM
anthonye
polynomial division and remainder theorem
Hi;

use remainder theorem to find the remainder of (3x^4 - 5x^2 - 20x -8) / (x + 1).

When using remainder theorem I get remainder -33

and with long division I get remainder 10 which I think is the right answer.

Not sure why I'm getting -33 with remainder theorem
What am I missing?

Thanks.
• Jul 30th 2012, 11:44 AM
a tutor
Re: polynomial division and remainder theorem
• Jul 30th 2012, 02:22 PM
skeeter
Re: polynomial division and remainder theorem
...

Code:

```-1] ... 3 ... 0 ... -5 ... -20 ... -8 .............-3 ....3.......2 ... 18 --------------------------------------- .......3.....-3....-2.....-18 ... 10```
• Aug 1st 2012, 12:08 AM
eumyang
Re: polynomial division and remainder theorem
Quote:

Originally Posted by anthonye
Hi;

use remainder theorem to find the remainder of (3x^4 - 5x^2 - 20x -8) / (x + 1).

When using remainder theorem I get remainder -33

and with long division I get remainder 10 which I think is the right answer.

Not sure why I'm getting -33 with remainder theorem
What am I missing?

Thanks.

Using the remainder theorem,
$f(-1)$
$= 3(-1)^4 - 5(-1)^2 - 20(-1) - 8$
$= 3 - 5 + 20 - 8$
$= 10$
• Aug 2nd 2012, 05:33 AM
anthonye
Re: polynomial division and remainder theorem
Yeah I got it thank you.