I suppose that you need to find the integral of the
function `sqrt((lnx)^2) ` such that:
`int sqrt((lnx)^2)
dx`
You need to remember that `sqrt(x^2) = |x|, ` hence
`sqrt((lnx)^2) = |ln x|`
`` `int sqrt((lnx)^2) dx = int |ln
x| dx`
You need to use integration by parts, hence you
should write the formula such that:
`int udv = uv - int
vdu`
You should consider `u = ln x =gt du = (dx)/x` ,
hence`dv = dx =gt v = x` Substituting `ln x` for u, `(dx)/x` for du, x for v and dx
for dv yields:
int |ln x| dx = x*|ln x| - int
x*(dx)/x
`int |ln x| dx = x*|ln x| - int
dx`
`int |ln x| dx = x*|ln x| - x + c =gt int |ln x| dx =
x*(|ln x| - 1) + ` c
`int |ln x| dx = x*(|ln x| - ln e) +
c`
`int |ln x| dx = x*|ln(x/e)| +
c`
Hence, evaluating the integral of function
yields `int sqrt((lnx)^2) dx = x*|ln(x/e)| + c` .
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