5.3,5.5-5.6 Flashcards
(24 cards)
What must be in order to use sum or differences of cubes?
must be cubed; also a two part formula
Sum or Difference of Cubes Formula
a3 + b3 = (a + b)(a2 – ab + b2)
a3 – b3 = (a – b)(a2 + ab + b2)
General Steps in sum or difference of cubes
divide by square root of 3 use the resulting numbers for a and b respectively plug into formula solve binomial quadratic formula
roots (also referred to as)
solutions of a polynomial equation (zero/solution/x-intercept)
Fundamental Theorem of Algebra
the degree (highest power) of a polynomial tells how many solutions exist
conjugate root theorem
all irrational and complex numbers come in pairs
rational root theorem
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)
Main Method
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
in synthetic division, each new repeat
the x value goes down 1 power
to solve a polynomial equation it must equal
zero
solve by factoring
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
i squared
-1
i cubed
-i
For the bonus, with squares and is and halves
just use foil and multiply
foiling for conjugates
only foil first and last, postitive I times -I=positive number
when checking the result of the quadratic
should be split
a polynomial with real coefficients has roots of 6,-2,-4i, and the square root of 5
negative square root of 5, 4i= all conjugates need a pair
list one method of solving this polynomial that works and why. Then list one method that doesn’t work and why. (5 part)
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
What is quadratic formula and why is it used when solving some polynomials
once you have used synthetic division (or is unfactorable) it will show imaginary or irrational roots
Is it possible to solve a polynomial by factoring using difference of cubes and difference of squares? Provide an example
Yes,(x squared-4) (x cubed-8)=x to the 5th+4x cubed+8x squared+32
when do u factor
when it is a trinomial and the powers are 4,2,0
how you can find a possible root
rational root theorem
explain which process you might try if the polynomial had
2-main method, sum/difference of cubes or squares
3-main method, GCF/factoring, power 4,2,0
4-main method
explain the relationship between an x-intercept, a factor, and synthetic division
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