Adding polynomials

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• Sep 16th 2011, 12:14 PM
vaironxxrd
Adding polynomials
Is my answer right?

$(3x^3&-5x^4&-10x&+1)&+(17x^4&-x^3)$

$(3x^3&-5x^4&-10x&+1)$
+ $(17x^4&-x^3)$

Answer = $12x^4&-x^3&-10x&+1$

I was told it does not have to be in standard form, but it helps to have it in standard form.. Is that true?
• Sep 16th 2011, 12:33 PM
Siron
Re: Adding polynomials
It's not entirely correct, because $3x^3-x^3=2x^3$ and not $-x^3$.
And to write the polynomial in a decraising way of the degrees is just a useful notation.
• Sep 17th 2011, 04:56 AM
vaironxxrd
Re: Adding polynomials
Quote:

Originally Posted by Siron
It's not entirely correct, because $3x^3-x^3=2x^3$ and not $-x^3$.
And to write the polynomial in a decraising way of the degrees is just a useful notation.

Oh, so is basically subtracting $3x^3-&1x^3$

By the way the exponents only cancel when dividing?
• Sep 17th 2011, 07:18 AM
Siron
Re: Adding polynomials
Quote:

Originally Posted by vaironxxrd
Oh, so is basically subtracting $3x^3-&1x^3$

Indeed!

Quote:

Originally Posted by vaironxxrd
By the way the exponents only cancel when dividing?

It depends, in general:
$\frac{a^{x}}{a^{y}}=a^{x-y}$
So if $x=y$ then indeed the exponent cancels.