100 likes | 173 Views
12.1 functions. Copy planner. functions. Functions are basically the same as equations, they are just written differently. F(x) means the function of “x” What value of “x” to use Y = 2x – 4 (equation) F(x) = 2x – 4 (function)
E N D
12.1 functions Copy planner
functions • Functions are basically the same as equations, they are just written differently. • F(x) means the function of “x” • What value of “x” to use • Y = 2x – 4 (equation) • F(x) = 2x – 4 (function) • Instead of have a “y” value, you use the f(x) to show what the function would equal with a specific value.
function • A function of “x” is a relationship in which no 2 ordered pairs have the same x-value • 3 types of functions to recognize • Linear function • Quadratic function • Exponential function • A graph that is not a function will have “x” values that are the same
Domain & range • Domain: all x-values that can be input into a function. • Range: the y-values or the “output” of the functions • Function or not a function (1,6) (3,6) (3,7) (8,9) (1,6) (2,6) (3,7) (8,9)
Evaluating a function • F(x) = 2x – 3 • X = -2 • Input -2 everywhere there is an “x” • F(-2) = 2(-2) – 3 • F(-2) = -7 • F(0) = • F(0) = -3
Real life functions • Functions are often used by companies to determine how to price their products. • X = cost of materials • Pricing function f(x) = 2x + 10 • X = 8 • F(8) = 2(8) +10 • F(8) = $26 • So, if the business spends $8 to make an item, they would charge a customer $26 to buy it.
review • What can a function NOT have? • No 2 ordered pairs w/the same x-value • What is the domain? • X-values • What is the range? • Y-values
12.2 linear functions • Linear function in slope-intercept form: • F(x) = mx + b • To write an ordered pair in function notation • f(-2) = 4 is the same as (2, -4)
Linear functions • Find a function for f(2) = 5 and f(6) = 3 • Remember, this is the same as having 2 points (2,5) and (6,3) • Find the slope • M = -1/2 • Substitute the slope into the function & 1 of the point to solve for the y-intercept, b • What is the function? • F(x) = -1/2(x) + 6 • When in doubt, treat like a regular equation