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Determime the domain of the function (f * g)(x) where f(x)=3x-1/x-4 and g(x)=x+1/x

 Sep 16, 2016
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Determime the domain of the function (f * g)(x) where f(x)=3x-1/x-4 and g(x)=x+1/x

 

(f * g) (x)  =

 

[ 3x -1 ] / [ x - 4 ]  *  [ x + 1/x ]

 

[3x^2 - x + 3 - 1/x]  / [ x - 4]   =

 

[3x^3 - x^2 + 3x - 1] / [ x (x - 4]

 

Note that the numerator will be defined for all x........the denominator will be 0 whenever x = 0   or x = 4

 

So....the domain is    ( -inf, 0 )  U (0, 4) U  (4 , inf )

 

Here's a graph :   https://www.desmos.com/calculator/hla8abgse6

 

 

 

 

cool cool cool

 Sep 16, 2016

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