Quadratic Equations and Complex Numbers Flashcards
Difference of squares
a² - b² = (a+b)(a-b)
How to solve a binomial with an exponent that isn’t 1
- Multiply the x² by the last number without x
- Find the two numbers that add up to the middle number and multiply to the new last number
- Keep the old last number in the new equation
How to find the zeros in a binomial
Factor the equation and solve each x with zero
Complex number
a+bi
What is a in a+bi
The real portion
What is bi in a+bi
The imaginary portion
What is √-1
i
What is i²
-1
What is the complex conjugate?
In imaginary factorials
(a+bi)(a-bi)
How to divide complex numbers
Multiply the top and bottom by the conjugate
(the opposite)
Ex. 3x-2; 3x+2
Every _ power of i; the pattern repeats itself
4th
What is the pattern of i
1
i
-1
-i
Steps to find what i to a power equals
- Divide the exponent by 4
- Remainder is the answer to the problem
What is a conjugate?
The same numbers but opposite addition/subtraction
How to complete the square
- a must = 1
- put a and b on the same side and c on the opposite side
- (b/2)²
- Factor
- Solve
Quadratic formula
x= -b+/- √(b)² - 4ac
2a
Steps to solve with the quadratic formula
- Identify a, b, c
- Substitute into the formula
- Simplify
If the discriminant is (+)
There are 2 real solutions
If the discriminant is (-)
There are 2 imaginary solutions
If the discriminant is (0)
There is 1 real solution
The pattern of i remainders
1: 1
1/4: i
1/2: -1
3/4: -i
What should the answer look like when asked to solve
Like solving for zeros
Ex. x=# x=-#
True or false…
Write +/- on all square root equations
True
Solve an equation using square roots
Put (x-#)² = # and take the square root of both sides