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7.3 Power Functions & Function Operations. p. 415. Sum : f(x) + g(x) = (f+g)(x). Difference : f(x) - g(x) = (f-g)(x). Product : f(x) * g(x) = (fg)(x). Quotient : . f(x) = 2x – 3 and g(x) =. Sum. Difference. Product. Quotient. Functions.
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Sum : f(x) + g(x) = (f+g)(x) Difference : f(x) - g(x) = (f-g)(x) Product : f(x) * g(x) = (fg)(x) Quotient :
f(x) = 2x – 3 and g(x) = Sum Difference Product Quotient
Functions In order for a relationship to be a function… EVERY INPUT MUST HAVE AN OUTPUT TWO DIFFERENT INPUTS CAN HAVE THE SAME OUTPUT ONE INPUT CAN HAVE ONLY ONE OUTPUT INPUT (DOMAIN) FUNCTIONMACHINE OUTPUT (RANGE)
Look on page 67 • No two ordered pairs can have the same first coordinate (and different second coordinates).
Time of Day Degrees C 3 15 1 6 2 4 9 1 11 4 12 7 6 13 2 5 10 3 8 5 14 Domain Inputs: 1,2,3,4,5,6 Contains the Range Outputs: 9,10,12,13,15
Ex. Is this a function? {(2,5) , (3,8) , (4,6) , (7, 20)} {(1,4) , (1,5) , (2,3) , (9, 28)} {(1,0) , (4,0) , (9,0) , (21, 0)}
Notation “f of x” Input = x Output = f(x) = y
Ex: Let f(x)=3x1/3 & g(x)=2x1/3. Find (a) the sum, (b) the difference, and (c) the domain for each. • 3x1/3 + 2x1/3 = 5x1/3 • 3x1/3 – 2x1/3 = x1/3 • Domain of (a) all real numbers Domain of (b) all real numbers
Ex: Let f(x)=4x1/3 & g(x)=x1/2. Find (a) the product, (b) the quotient • 4x1/3 * x1/2 = 4x1/3+1/2 = 4x5/6 = 4x1/3-1/2 = 4x-1/6 =
Evaluate (f-g)(x) when x = 2 for the functions (f - g)(x) = (f - g)(2) =
Composition • f(g(x)) means you take the function g and plug it in for the x-values in the function f, then simplify. • g(f(x)) means you take the function f and plug it in for the x-values in the function g, then simplify.
The COMPOSITION of the function f with g is Plug the second function into the first
Ex: Let f(x)=2x-1 & g(x)=x2-1. Find (a) f(g(x)), (b) g(f(x)), (c) f(f(x)) (a) 2(x2-1)-1 = (c) 2(2x-1)-1 = 2(2-1x) = (b) (2x-1)2-1 = 22x-2-1 =
A clothing store is having a sale in which you can take $50 off the cost of any coat in the store. The store also offers 10% off your entire purchase if you open a charge account. You decide to open a charge account and buy a coat. Use composition of functions to find the sale price of a $175 coat when $50 is subtracted before the 10% discount is applied.