Algebra Flashcards
Average rate of change
The average rate of change of function f over the interval a≤ x ≤b is given by this expression:
f(b) – f(a) / b – a
Greatest common monomial factor
Greatest integer and variable that is a factor of both numbers
10x^3 2 5 x x x
4x 2 2 x
GCF = 2x
Maximum amount of a quadratic function in a word problem
The x-coordinate of the vertex, which is the average of the two zeros. when it asks for maximum x this is answer?
Need to put the x-coordinate back into equation when it asks for maximum f of whatever. f(x)
Takeoff/liftoff height in quadratic function word problem
When x equals 0
km/h to m/s
x km/h * 1000m/1 km * 1 h/3600 s
Shifting absolute value graphs
f(x) = a|x - h| + k a = how far graph stretches vertically, and whether it opens up or down h = how far graph shifts horizontally (- right(input +), + left (input -)) k = how far graph shifts vertically
Finding vertex (max/min) of a parabola (quadratic function)
For the x-value: -b/2a (ax^2 + bx + c)
For the y-value: plug x value into equation
degrees/min^2 to degrees/sec^2
x degrees/min^2 * 1 min^2/3600 sec^2 (60 * 60)
Shifting parabolas
(x - k)^2 + h
k = left/right - right + left
h = up/down
g(x) = a * b^x
a is the value of the function when x = 0 (y of y-intercept)
b is the constant ratio of g(x) for consecutive integer values of x
constant ratio: divide the y value of (1, y) by the y value of (0, y) (y-intercept)
g(r) = (r + n1)^2 + n2
(r + n1)^2 + n2 = 0 (r + n1)^2 = --n2 sqrt((r + n1)^2) = sqrt(--n2) r + n1 = +/- of sqrt(--n2) r = (+/- of sqrt(--n2)) -- n1 zeros: + sqrt(--n2) -- n1 AND --sqrt(--n2) -- n1 vertex: (--n1, n2)
point-slope formula
y - y1 = m(x - x1)
(x1, y1) = known point
m = slope
(x, y) = second point on the line, stays (x,y)?
slope formula
change in y / change in x
y2 - y1 / x2 - x1
explicit formula of geometric sequence
a(n) = k * r^(n-1)
recursive formula of geometric sequence
a(1) = k a(n) = a(n-1) * r
number of solutions to linear equations
1 = all EXCEPT 0 = parallel lines, aka same slope infinite = same line
completing the square
ax^2 + bx + c = 0 x^2 + (b/a)x + c/a = 0 x^2 + (b/a)x = --c/a OR ax^2 + bx + c = 0 a(x^2 + (b/a)x) + c = 0 d = completed square a(x^2 + (b/a)x) +d) + (c - (a*d)) e = completed square in (x - e)^2 form a(x - e)^2 + (c - (a*d))
find the nth term in the arithmetic sequence
(n-1) = the term before n, plug into equation to get n
recursive formula of arithmetic sequence
a(1) = k a(n) = a(n-1) + r
explicit formula of arithmetic sequence
a(n) = k + r(n-1)
simplifying square roots
- factor the number under the radical
- when you find a perfect square, take it out and put it (once) in front of the radical
- do this until the number under the radical can’t be factored out (if more than one perfect squares in front of radicals, multiply them)
x times old problem
y number of years it will take to be x times as old
a1 + y a2 + y a = age
a1 + y = x(a2 + y)
simplify and solve for y
0^3
0
1^3
1
2^3
8
3^3
27
4^3
64
5^3
125
6^3
216
7^3
343
8^3
512
9^3
729
10^3
1000
11^3
1331
12^3
1728
13^3
2197
14^3
2744
15^3
3375
integer vs. real number
Integer – no fractions, counting (can be negative)
Real number – fractions
domain of a function
set of all real values of x that will give real values for y (input)