The function f is defined as f(x) = e^(x-4). Find the inverse of f and state its domain.

Firstly, we let y=f(x) so that y=ex-4. The aim of this question is to find the inverse of y=f(x), and in order to do that, we must rearrange the question so that x becomes the subject of the equation, which will be our inverse function of f. The first step is to eliminate the exponential by applying the loge function to each side of the equation, as loge(ex) = x. Therefore, we get: loge(y)=loge(ex-4), loge(y)=x-4, x=loge(y)+4. Now we have x the subject of the equation, the inverse is loge(y)+4. The question is asking about the inverse of f(x) so we replace y with x and obtain f-1(x) = loge(x) + 4.The domain of f-1(x) is the set of input values that f(x) accepts, so we must find those values. We know that the domain of log(x) only takes values above 0, therefore the domain of f-1(x) is 0 < x < +infinity.

Answered by Rutwik K. Maths tutor

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