Raymond B. answered 03/02/26
Math, microeconomics or criminal justice
int logx = xlogx -x +c
check the answer
(xlogx-x+c)'= x(1/x)+logx(1)-1+0= logx
Raymond B. answered 03/02/26
Math, microeconomics or criminal justice
int logx = xlogx -x +c
check the answer
(xlogx-x+c)'= x(1/x)+logx(1)-1+0= logx
Dayv O. answered 03/09/25
Caring Super Enthusiastic Knowledgeable Calculus Tutor
For the area beneath y=ln(x) to x-axis
see Mark's answer, and use definite integral.
from x=1 to x=e the area =[e*1-e]-[1*0-1]=1 sq unit.
from x=1 to arbitrary x>1 the area =[xlnx-x]-[1*0-1]=xlx-x+1+1,,,kind of cool, like 'rectangle-x" plus 1
For area beneath y=log10 (x) to x-axis
see Doug's answer and use definite integral
from x=1 to x=10 the area =[10*1-(10/ln10)]-[1*0-(1/ln10)]=10-(9/ln(10))
Mark M. answered 03/09/25
Retired math prof. Calc 1, 2 and AP Calculus tutoring experience.
If you mean lnx, use integration by parts with u = lnx and dv = dx.
Then, du = (1/x)dx and v = ∫dv = x.
So, ∫ lnxdx = ∫udv = uv - ∫vdu = xlnx - ∫dx = xlnx - x + C
Doug C. answered 03/08/25
Math Tutor with Reputation to make difficult concepts understandable
Assuming the post really intends common log.
Integration by parts.
u = log x
dv = ∫dx
du = 1/(xln(10)) dx
v = x
I = xlogx - ∫x(1/xln10)dx
I = xlogx - x/ln(10) + C
desmos.com/calculator/xdulajug4d
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