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f(x)=√(x-1) ; g(x)=1/(x-7)

2007-07-08 18:16:42 · 2 answers · asked by Anonymous in Science & Mathematics Mathematics

2 answers

well, x cannot be 7 since that would make g(x) undefined, and 1/(x-7) -1 must be greater (or equal) to 0 or else f(x) would be undefined. So 1/(x-7) ≥ 1, 1 ≥ x - 7, 8 ≥ x. But also, x-7 > 0 else g(x) goes negative and leaves f(x) undefined.

So 7 < x ≤ 8 is the domain. Graph it to verify.

2007-07-08 18:47:48 · answer #1 · answered by Philo 7 · 0 0

g(x)-1 >= 0
1/(x-7) - 1 >= 0
1 - 1/(x-7) <= 0
(x-8)/(x-7) < = 0, x!= 7
Therefore, the domain of x is (7,8].

2007-07-08 18:31:30 · answer #2 · answered by sahsjing 7 · 0 1

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