Simple Indefinite Integral of \int\frac{4}{-e^{4x-7}} = ln(-e^{4x-7}) = -4x+7+C

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\int\frac{4}{-e^{4x-7}}

=ln-e^{4x-7}}

=-4x+7+C

The answer says it is:

=\-e^{-4x+7}+C
 
Last edited:
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The book is right, which is easily verifiable by computing the derivative the given answer.
 
D H said:
The book is right.

Is there somewhere I went wrong? I am guessing it has something to do with the ln.
I thought that

\ln{e}=1

Therefore: ln-e^{4x-7}}=-4x+7+C
 
Last edited:
Yes, the problem is with the natural logarithm.

Just because \int \frac 1 x \,dx = \ln x does not mean that everything of the form \int \frac 1{f(x)}\,dx integrates to \ln(f(x)).
 
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