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Question
Evaluate:
`int log x dx`
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Solution
Let `I = int log x dx`
= `int log x * 1 dx`
`I = log x int 1 dx - int [int 1 dx * d/dx (log x)] dx`
= `(log x) (x) - int [x * 1/x] dx`
= `x log x - int 1 dx`
∴ I = x log x − x + c
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