5.3,5.5-5.6 Flashcards

(24 cards)

1
Q

What must be in order to use sum or differences of cubes?

A

must be cubed; also a two part formula

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2
Q

Sum or Difference of Cubes Formula

A

a3 + b3 = (a + b)(a2 – ab + b2)

a3 – b3 = (a – b)(a2 + ab + b2)

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3
Q

General Steps in sum or difference of cubes

A
divide by square root of 3 
use the resulting numbers for a and b respectively
plug into formula
solve binomial
quadratic formula
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4
Q

roots (also referred to as)

A

solutions of a polynomial equation (zero/solution/x-intercept)

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5
Q

Fundamental Theorem of Algebra

A

the degree (highest power) of a polynomial tells how many solutions exist

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6
Q

conjugate root theorem

A

all irrational and complex numbers come in pairs

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7
Q

rational root theorem

A

for the real roots of a polynomial equation, a list of possible solutions can be created in the form ;
+ factors of the constant term (last)
- factors of the leading coefficient (first)

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8
Q

Main Method

A

Graph to find rational roots, use those zeros in synthetic division to reduce the powers to a square, and solve the remaining quadratic equation by the quadratic formula

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9
Q

in synthetic division, each new repeat

A

the x value goes down 1 power

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10
Q

to solve a polynomial equation it must equal

A

zero

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11
Q

solve by factoring

A

divide out GCF if necessary, factor the quadratic or perfect quartic equation using the ac/b chart , set factor equal to zero and solve. (if factoring didn’t work use quadratic formula) #set GCF to 0

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12
Q

i squared

A

-1

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13
Q

i cubed

A

-i

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14
Q

For the bonus, with squares and is and halves

A

just use foil and multiply

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15
Q

foiling for conjugates

A

only foil first and last, postitive I times -I=positive number

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16
Q

when checking the result of the quadratic

A

should be split

17
Q

a polynomial with real coefficients has roots of 6,-2,-4i, and the square root of 5

A

negative square root of 5, 4i= all conjugates need a pair

18
Q

list one method of solving this polynomial that works and why. Then list one method that doesn’t work and why. (5 part)

A

cube root won’t work because you can’t cube root all these numbers
not 3 terms;unfactorable
Main method works because the calc. gives numbers and you can use synthetic division to find rest

19
Q

What is quadratic formula and why is it used when solving some polynomials

A

once you have used synthetic division (or is unfactorable) it will show imaginary or irrational roots

20
Q

Is it possible to solve a polynomial by factoring using difference of cubes and difference of squares? Provide an example

A

Yes,(x squared-4) (x cubed-8)=x to the 5th+4x cubed+8x squared+32

21
Q

when do u factor

A

when it is a trinomial and the powers are 4,2,0

22
Q

how you can find a possible root

A

rational root theorem

23
Q

explain which process you might try if the polynomial had

A

2-main method, sum/difference of cubes or squares
3-main method, GCF/factoring, power 4,2,0
4-main method

24
Q

explain the relationship between an x-intercept, a factor, and synthetic division

A

factor is solution to equation. when solve, factor is an x-intercept. to check that a factor is a solution we use synthetic division to check its remainder. If the remainder is 0 the factor is an x-intercept