# enrick

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1. What is a function?
A function f is a set rule that assigns to each element x in aset A exactly one element, called f(x) in a set B
2. What is the independant variable and what is the dependant variable of y = f (x)
y is the dependant variable, & x independant variable
3. Squaring the fuction: f(x)=x2
a) evaluate f(3), f(√5)
b) find domain and range of f
• a) f(3)= 32 = 9, f (√5)=√52=25
• b) all real numbers f is ⎨y⎮y≥0, ⎬[0,∞)
4. Evaluating a Function: f(x) = 3x2+ x - 5 ; f(-2)
• f(-2) = 3(-2)2+ (-2) - 5
• = 12 - 2 -5
• = 5
5. Evaluating a Function: f(x) = 2x2 + 3x - 1
f(a)
f(-a)
f(a+h)
f(a+h) - f(a) /h; h≠0
• f(a) = 2a2 + 3a - 1
• f(-a)=2(-a)2+3(-a)-1 = 2a2-3a-1
• f(a+h) = 2(a+h)2 +3(a+h) - 1
• = 2(a2+2ah+h2) +3a+3h - 1
• = 2a2+4ah+2h2+3a+3h - 1
• f(a+h) - f(a) /h
• = (2a2+4ah+2h2+3a+3h - 1) -(2a2+ 3a - 1)/h
• = 2a2+4ah+2h2+3a+3h - 1 -2a2- 3a + 1)/h
• = 4ah+2h2/h
• = h(4a+2h)/h
• = 4a+2h
 Author: enrick ID: 92430 Card Set: enrick Updated: 2011-06-30 10:40:20 Tags: Pre Cal Math Folders: Description: 2.1 Functions Show Answers: