Mister Exam

Integral of arctan dx

Limits of integration:

from to
v

The graph:

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Piecewise:

The solution

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01atan(x)dx\int\limits_{0}^{1} \operatorname{atan}{\left(x \right)}\, dx
Integral(atan(x), (x, 0, 1))
Detail solution
  1. Use integration by parts:

    udv=uvvdu\int \operatorname{u} \operatorname{dv} = \operatorname{u}\operatorname{v} - \int \operatorname{v} \operatorname{du}

    Let u(x)=atan(x)u{\left(x \right)} = \operatorname{atan}{\left(x \right)} and let dv(x)=1\operatorname{dv}{\left(x \right)} = 1.

    Then du(x)=1x2+1\operatorname{du}{\left(x \right)} = \frac{1}{x^{2} + 1}.

    To find v(x)v{\left(x \right)}:

    1. The integral of a constant is the constant times the variable of integration:

      1dx=x\int 1\, dx = x

    Now evaluate the sub-integral.

  2. The integral of a constant times a function is the constant times the integral of the function:

    xx2+1dx=2xx2+1dx2\int \frac{x}{x^{2} + 1}\, dx = \frac{\int \frac{2 x}{x^{2} + 1}\, dx}{2}

    1. Let u=x2+1u = x^{2} + 1.

      Then let du=2xdxdu = 2 x dx and substitute du2\frac{du}{2}:

      12udu\int \frac{1}{2 u}\, du

      1. The integral of 1u\frac{1}{u} is log(u)\log{\left(u \right)}.

      Now substitute uu back in:

      log(x2+1)\log{\left(x^{2} + 1 \right)}

    So, the result is: log(x2+1)2\frac{\log{\left(x^{2} + 1 \right)}}{2}

  3. Add the constant of integration:

    xatan(x)log(x2+1)2+constantx \operatorname{atan}{\left(x \right)} - \frac{\log{\left(x^{2} + 1 \right)}}{2}+ \mathrm{constant}


The answer is:

xatan(x)log(x2+1)2+constantx \operatorname{atan}{\left(x \right)} - \frac{\log{\left(x^{2} + 1 \right)}}{2}+ \mathrm{constant}

The answer (Indefinite) [src]
  /                    /     2\            
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 | atan(x) dx = C - ----------- + x*atan(x)
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atan(x)dx=C+xatan(x)log(x2+1)2\int \operatorname{atan}{\left(x \right)}\, dx = C + x \operatorname{atan}{\left(x \right)} - \frac{\log{\left(x^{2} + 1 \right)}}{2}
The graph
0.001.000.100.200.300.400.500.600.700.800.900.01.0
The answer [src]
  log(2)   pi
- ------ + --
    2      4 
log(2)2+π4- \frac{\log{\left(2 \right)}}{2} + \frac{\pi}{4}
=
=
  log(2)   pi
- ------ + --
    2      4 
log(2)2+π4- \frac{\log{\left(2 \right)}}{2} + \frac{\pi}{4}
-log(2)/2 + pi/4
Numerical answer [src]
0.438824573117476
0.438824573117476
The graph
Integral of arctan dx

    Use the examples entering the upper and lower limits of integration.