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# Another C3 functions question

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Why bother with a post grad course - waste of time? 17-10-2016
1. The function f is defined by f : x → 3 + ln (x + 2), x ∈ R , x ≥ k, where k is a constant. Given that the range of f is f(x) ≥ 3,

a) find the value of k,

b) find f −1(x), stating its domain clearly.

Can someone tell me if I have answered this question correctly?

For part a), I drew a graph of the function and worked out that when y=3, x=-1, therefore the domain must be x ≥ -1, therefore k = -1.

For part b) I worked out that the inverse function is ex-3 -2 which I am not sure is correct.
I don't know how to find the domain for this though... How do you do it?
2. (Original post by jessyjellytot14)
...
Domain of the inverse is the range of the original. Remember what happens with y and x when it comes to the inverse, apply the same idea to the constraints.

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