Question 630997
composite function.. 
f(x)=x^2 - 1
g(x)= 1/sqrt x + 1 
fog(x) = f[g(x)] 
= f[1/sqrt(x+1] 
= [1/sqrt(x+1)]^2 -1 
= x+1-1 
= x
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Cheers,
Stan H.