please see attached. my question is how do i form the exponents
Example: 2x2x2x2 would be 2^4
did you look at the attachment???
for the 1st example notice that the first line, all the terms have exponents that add up to 4 each term is alphabetical ab they start with the highest exponent (4) for a and the lowest for b (0) a^4 b^0 is just a^4 * 1 or just a^4 then you go down 1 on the a exponent and up 1 on the b exponent.
In the first line, the exponents of the ab terms add to 4 in the 2nd line the exponents of the ab terms add to 3 the answer line, the exponents add to 4+3 = 7 so the answer is in the order a^7 b^0 a^6 b^1 a^5 b^2 .... a^1 b^6 a^0 b^7
but there is no a^6
notice that you multiply all these ab terms by the coefficients of the calculation the coeff for a^6 b^1 is 0, so we don't bother to write it down
sorry i am completely lost
what do you mean when you said the "the first all the terms have exponent that add up to 4"????
I meant in the first equation: a^4 - 3a^2b^2 .... notice that a^4 is the same as a^4 b^0 (right?) and 4+0=4 in -3a^2 b^2 we again have 2+2=4 and so on for each term...
ok
is the coefficient for a^6 b^1 zero because it is not in either of the original equations???
It looks like it. But notice they got a zero for a^4b^3 which happened because things canceled. to use this technique they started with \[ a^4 -3a^2b^2 +2ab^3+b^4\] they then make a grid with the exponents for a and b 4,0 3,1 2,2 1,3 0,4 (I'm abbreviating here. those are the exponents) then they fill in the coefficients in the correct column 4,0 3,1 2,2 1,3 0,4 1 -3 2 1 if any are missing, put in a zero 4,0 3,1 2,2 1,3 0,4 1 0 -3 2 1
they did the same thing for the other polynomial to get 1 0 -2 -2 then they put one set of coefficients below the other, lining up on the left side (this is different from when we do 312 x 21 where we line them up on the right side) 1 0 -3 2 1 1 0 -2 -2 then they multiply going left to right the first 1 in the bottom times every number in the top row gives you 1 0 -3 2 1 then mult by 0 and go in one place to the right: 1 0 -3 2 1 0 0 0 0 then -2 times the top row. put the answer starting below the -2 1 0 -3 2 1 0 0 0 0 -2 0 6 -4 -2 then the last -2 times the top row 1 0 -3 2 1 0 0 0 0 -2 0 6 -4 -2 -2 0 6 -4 -2 then add up the columns 1 0 -5 0 7 2 -6 -2 now assign ab with the correct exponents
7,0 6,1 5,2 4,3 3,4 2,5 1,6 7 1 0 -5 0 7 2 -6 -2
\[ a^7 -5a^5b^2 +7a^3b^4 +2a^2b^5 -6ab^6 -2b^7 \]
thanks phi
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