Question

Find the domain of each function. (Enter your answers using interval notation.)(a) f(x)=8/(1+e^x) .(b) f(x)=5/(1−e^x)

Answer 1

domain is (-∞,∞)

(-∞,0) U(0,∞)

Explanation:

`f(x)=(1)/(1+e^x)`

The domain is the set of x values for which the function is defined

In f(x) there is no restriction for x. the function is defined for all x values

so domain is (-∞,∞)

`f(x)=(5)/(1-e^x)`

The domain is the set of x values for which the function is defined

when x=0, e^0=1 that makes the denominator 0

Denominator 0 is undefined. So x cannot be 0

domain is (-∞,0) U(0,∞)