The domain of the function f(x)=5/(1+e^x) (in interval notation)

what is the main concern here? when looking at fractions, what gives us troubles?

Well I know 2<e<3 and I also know that x is not equal to zero but I do not know how to express the answer in interval form.

.... the domain of a function are all the values that we are allowed to use that will not make our function go bad. fractions go bad when we divide by zero right? when does 1+e^x = 0?

That's where I get stuck. I just don't know how to work out the problem to get the answer.

the answer lies in knowing something about e^x; this always produces a positive value. 1 + some positive value is never 0; so our domain, the stuff we are allowed to use for "x" is not restricted in any way: D = (-inf,inf)

Thank you! It was the "e" throwing me off the whole time. I felt like I needed to divide it or do natural log for some reason.

you could have tried to log it but the effects the same without knowing the properties of exponential and logarithmic functions. 1+ e^x = 0 e^x = -1 ln(e^x = -1) x = ln(-1) ; since the value of ln(-1) is not defined for the real number set; its just something that has to be "known"

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