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f g = f ( g ( x )) = (2 x + 1) 2 – 3(2 x + 1). Composite Functions. Example 1: Given functions f ( x ) = x 2 – 3 x and g ( x ) = 2 x + 1, find f g.
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f g = f (g(x)) = (2x + 1)2 – 3(2x + 1) Composite Functions Example 1: Given functions f(x) = x2 – 3x and g(x) = 2x + 1, find f g. The notation "f g" means f (g(x)). In other words, replace x in function f with 2x + 1 (the g function). f g= f (g(x)) = (x)2 – 3(x) f g= 4x2 + 4x + 1 – 6x – 3 f g= 4x2 – 2x – 2
Example 2: Given functions and find f g and state its domain. x x Composite Functions Simplify the complex fraction by multiplying the numerator and denominator by x + 1. Slide 2
Composite Functions At first glance it might appear that the domain of f g is the set of all real numbers except - 1.5. Slide 3
However, remember that the g function, replaced x in the f function. Therefore, the domain of f g is: ( - , - 1.5 ) ( - 1.5, - 1 ) ( - 1, ). Composite Functions Since the g function is not defined for x = - 1, neither is the f g function. Slide 4
Try: Given functions and find f g and state its domain. The composite function, f g = x. Its domain is: [ - 5, ). Composite Functions Slide 5
Composite Functions END OF PRESENTATION Click to rerun the slideshow.