Polynomials

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aardon
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Joined: Sun Jul 31, 2011 4:13 pm
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Polynomials

Postby aardon » Sun Jul 31, 2011 4:34 pm

I'm trying to figure out how my book came up with it's answer. I've worked and reworked this but come up with anything but their answer. Here's what I'm trying to accomplish.

Evaluate the expression:
y^4 - y^3 + y^2 + 2y - 1

Let y = -1

I interpreted it to read:
-1^4 + -(-1)^3 + (-1)^2 + 2(-1) + (-1)
-1 + (1) + 1 +(-2) + (-1)
-1 + 2 + (-2) + -1
1 + -3
-2

The book says, "0" but I get "-2"

I'd like to see what you might evaluate it to.

Thanks!
:popcorn:

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little_dragon
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Re: Polynomials

Postby little_dragon » Sun Jul 31, 2011 7:37 pm

aardon wrote:Evaluate the expression:
y^4 - y^3 + y^2 + 2y - 1

Let y = -1

I interpreted it to read:
-1^4 + -(-1)^3 + (-1)^2 + 2(-1) + (-1)

it looks like U did the 4 on the 1 but not the -
U have to do the 4 on all of y
(-1)4=(-1)(-1)(-1)(-1)=1

:wave:


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