Respuestas

2013-10-09T22:57:11+02:00
I'm going to find the composite function for you first. 

Think of g(x) = sqrt(x - 4) as g(anything) = sqrt(anything - 4) 

Think of f(x) = 1/x as anything. 

then, since g(anything) = sqrt(anything - 4) 

g(f(x)) = sqrt( f(x) - 4 ) = 

sqrt( (1/x) - 4)...<<< Second Answer - composite function 
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As to the domain, f(x) is not defined for x = 0 and 

g(z) is not defined over negative numbers since the square root of a negative number is a complex number, which in this case means it doesn't exist. 

So ((1/x) - 4) >= 0.....Multiply both sides of the inequality by x for x positive (it can't be negative). 

x - 4 => 0, so x => 4 

{x | x=> 4}...<<< First Answer - domain