If f(x) = log x and g(x) = 1/(x-7), what is the domain of g(f(x))?
So g(f(x)) = 1/(logx-7)
I was a bit confused with the domain of a reciprocal function...
Options:
a) {x e R| x > 0}
b) {x e R | x can't equal 7}
c) {x e R | x > 0 and x can't equal 10 000 000}
d) {x e R | x can't equal 10 000 000}
g( f(x) ) = 1 / ( log x - 7 )
There are two things that we need to consider.
Since log x is part of the function, we have the restriction x > 0 .
Since log x - 7 is in a denominator, we have the restriction log x - 7 ≠ 0 .
log x ≠ 7
x ≠ 107
x ≠ 10 000 000
So the domain is all real x values such that x > 0 and x ≠ 10 000 000
g( f(x) ) = 1 / ( log x - 7 )
There are two things that we need to consider.
Since log x is part of the function, we have the restriction x > 0 .
Since log x - 7 is in a denominator, we have the restriction log x - 7 ≠ 0 .
log x ≠ 7
x ≠ 107
x ≠ 10 000 000
So the domain is all real x values such that x > 0 and x ≠ 10 000 000