Algebra - FOIL Bi/Tri nomials to the nth power

In summary, the conversation discusses determining coefficients by using a rule and looking at the numbers in the line for coefficients rather than the coefficients of the terms in the bottom line for multiplying. The instructions on the page may not work if the coefficients are not 1. The conversation also mentions adjusting for exponents in binomial expansions and the usefulness of this technique in calculus.
  • #1
Miike012
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I added an attachment with my question highlited.

How was the coeficient 6, 4, and 1 determined.

by rule 6 the coeficient should be 8*3/(2+1) = 8.

Please help.
Thank you.
 

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  • #2
It looks like you're supposed to look at the numbers in the line for Coefficients rather than the coefficients of the terms in the bottom line for Multiplying. The instructions on that page work out only if both terms in the binomial have a coefficient of 1.
 
  • #3
Ok well how am I suppose to figure out the coefficient if that line isn't given?
 
  • #4
Instead of looking at the 8 in the bottom line, use the 4 right above it. Do the same thing for each following coefficient.
 
  • #5
did that already.. it turns out that if I used the 4 instead of the 8.. the next coef. would be 4 rather than 6.. which doesn't work.
 
  • #6
Not only is that 2 in front of the b messing up the instructions, but that 2 exponent is too...
Before you actually use the exponent on your b to get the next coefficient, divide it's exponent by the exponent that b has in the original binomial in parentheses; in this case divide the exponents of b by 2 before you actually use them to find the coefficient.
 
  • #7
thank you. it makes sense now. I will be starting calc this upcoming semester, will this technique be useful?
 
  • #8
Probably not; I don't think I saw binomial expansions at all in calc I or II.
 

1. What is FOIL in Algebra?

FOIL is an acronym that stands for First, Outer, Inner, Last. It is a method used to multiply two binomials (expressions with two terms) together. The method involves multiplying the first terms, then the outer terms, then the inner terms, and finally the last terms. This helps to ensure that all possible combinations are accounted for in the product.

2. How do you FOIL two binomials together?

To FOIL two binomials together, you first multiply the first terms together, then the outer terms, then the inner terms, and finally the last terms. For example, if you have (x+2)(y+3), you would first multiply x and y to get xy, then the outer terms (x and 3) to get 3x, then the inner terms (2 and y) to get 2y, and finally the last terms (2 and 3) to get 6. The final product would be xy+3x+2y+6.

3. How can FOIL be extended to trinomials?

FOIL can be extended to trinomials by using the distributive property. For example, if you have (x+2)(x+3), you would first multiply the first terms (x and x) to get x^2, then the outer terms (x and 3) to get 3x, then the inner terms (2 and x) to get 2x, and finally the last terms (2 and 3) to get 6. The final product would be x^2+3x+2x+6, which simplifies to x^2+5x+6.

4. Can FOIL be used to multiply more than two binomials together?

Yes, FOIL can be extended to multiply more than two binomials together. The process would be similar to multiplying two binomials, but you would have to apply the FOIL method multiple times to account for all possible combinations. For example, if you have (x+2)(y+3)(z+4), you would first FOIL (x+2)(y+3) to get xy+3x+2y+6, and then FOIL that result with (z+4) to get xyz+3xz+2yz+6x+4y+24.

5. How does FOIL relate to the Binomial Theorem?

The Binomial Theorem is a formula used to expand binomial expressions raised to a power. FOIL is a method that can be used to multiply binomials together, and it is often used as a shortcut when applying the Binomial Theorem. By using FOIL, you can quickly find the coefficients of each term in the expanded binomial expression without having to use the Binomial Theorem formula for each term.

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