i will coach each step as you asked. 2·? x·ln(2x) dx u = ln(2x) du = [a million/x] dx dv = x dx v = ½·x² ? u dv = uv - ? v du 2·? x·ln(2x) dx = 2·[ ½·x²·ln(2x) - ? ½·x²·[a million/x] dx 2·? x·ln(2x) dx = 2·[ ½·x²·ln(2x) - ½·? x dx] 2·? x·ln(2x) dx = 2·[ ½·x²·ln(2x) - ¼·x²] + C 2·? x·ln(2x) dx = x²·ln(2x) - ½·x² + C
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It might help to do a substitution t = 2x + 1, dt = 2dx first.
∫ ln(2x + 1) dx = ∫ ½ ln(t) dt
Now, for parts, take u = ln(t), du = 1/t dt and dv = dt so v = t
∫ ½ ln(t) dt = ½[ t ln(t) - ∫ t(1/t) dt] = ½ t ln(t) - ½ ∫ dt = ½ t ln(t) - ½ t + C.
Going back to x
∫ ln(2x + 1) dx = ½(2x + 1) ln(2x + 1) - ½(2x + 1) + C.
This can be written slightly differently. Since ½(2x + 1) = x + ½, you can combine the ½ in this sum with the constant C of integration and write
∫ ln(2x + 1) dx = ½(2x + 1) ln(2x + 1) - x + C.
By parts:
u = ln (2x + 1), du = 2/(2x+1), dv = dx, v = x
uv - Integral v du = x ln(2x+1) - Integral 2x/(2x+1) dx
Integral of 2x/(2x + 1) dx = Integral of 1 - 1/(2x+1) dx = x - 1/2 ln (2x + 1)
Answer: x ln (2x +1) - x + 1/2 ln (2x+1) + C
∫ ln(2x+1) is integrated by parts.
∫ ln(2x+1) = ln(2x+1) ∫1.dx - ∫[(2x+1)'. ∫1.dx].dx
= ln(2x+1)(x) - ∫[(2+0).(x)]dx
= ln(2x+1)(x) - 2 ∫xdx
= ln(2x+1)(x) - 2(x^2/2) + c
= ln(2x+1)(x) - x^2 + c
Thats the answer.whenever u get to integrate LOG or INVERSE TRIGNOMETRIC integral always consider the 1st function and integrate them by parts
i will coach each step as you asked. 2·? x·ln(2x) dx u = ln(2x) du = [a million/x] dx dv = x dx v = ½·x² ? u dv = uv - ? v du 2·? x·ln(2x) dx = 2·[ ½·x²·ln(2x) - ? ½·x²·[a million/x] dx 2·? x·ln(2x) dx = 2·[ ½·x²·ln(2x) - ½·? x dx] 2·? x·ln(2x) dx = 2·[ ½·x²·ln(2x) - ¼·x²] + C 2·? x·ln(2x) dx = x²·ln(2x) - ½·x² + C
Let u = 2x + 1, du = 2dx, dx = du/2
Now integrate by parts.
v = ln(u), dv = dx/x
w = u, dw = du
∫ln(2x + 1)dx = vw – 1/2∫u du = 1/2[(2x + 1)ln(2x + 1) – 2x + 1] + K
use the tabular method and put ln(2x+1) as your U and DX as you DV
u would derive to 1/[2(2x+1)] and DX would integrate to x then you would get
xln(2x+1)- ∫x/[2(2x+1)]dx
you can probably solve from there but i'll put the rest down
xln(2x+1)-1/2∫x/(2x+1)
then u=2x+1
1/2du=dx
x=(u-1)/2
xln(2x+1)-1/8∫(u-1)/u du
xln(2x+1)-1/8∫1-1/u du
then intigrate
xln(2x+1)-1/8u+1/8ln|u|+c
xln(2x+1)-1/8(2x+1)+1/8ln|2x+1|+C
t = 2x + 1
dt = 2dx
ln(2x + 1) * dx =
ln(t) * (1/2) * dt =
(1/2) * ln(t) * dt
int((1/2) * ln(t) * dt) =
(1/2) * int(ln(t) * dt)
u = ln(t)
du = dt/t
dv = dt
v = t
(1/2) * int(u * dv) =
(1/2) * (uv - int(v * du)) =
(1/2) * (t * ln(t) - int(t * dt / t)) =
(1/2) * (t * ln(t) - int(dt)) =
(1/2) * (t * ln(t) - t) + C =
(1/2) * (t) * (ln(t) - 1) + C
t = 2x + 1
(1/2) * (2x + 1) * (ln(2x + 1) - 1) + C
Let u = ln(2x+1) so du = 2dx/(2x+!)
Let dv = dx so v = x
uv - ∫vdu = xln(2x+1) - ∫2x/(2x+1)dx
uv - ∫vdu = xln(2x+1) - [∫(2x+1 - 1)/(2x+1)dx]
uv - ∫vdu = xln(2x+1) - ∫(2x+1)/(2x+1)dx + ∫1/(2x+1)dx
uv - ∫vdu = xln(2x+1) - x + ½ln(2x+1)
uv - ∫vdu = (x - uv - ∫vdu = (x+½)ln(2x+1) - x