Math Problem Statement

arctan(√6x−1)

Calculate indefinite integrals

Solution

To find the indefinite integral of arctan(6x1)\arctan(\sqrt{6x - 1}), we will use integration by parts. The integration by parts formula is:

udv=uvvdu\int u \, dv = uv - \int v \, du

Let's set u=arctan(6x1)u = \arctan(\sqrt{6x - 1}) and dv=dxdv = dx.

First, we need to find dudu and vv:

  1. Finding dudu:

    u=arctan(6x1)u = \arctan(\sqrt{6x - 1})

    Let t=6x1t = \sqrt{6x - 1}, then:

    u=arctan(t)u = \arctan(t)

    dtdx=626x1=36x1\frac{dt}{dx} = \frac{6}{2\sqrt{6x - 1}} = \frac{3}{\sqrt{6x - 1}}

    Therefore,

    dudx=ddxarctan(t)dtdx=11+t236x1\frac{du}{dx} = \frac{d}{dx} \arctan(t) \cdot \frac{dt}{dx} = \frac{1}{1 + t^2} \cdot \frac{3}{\sqrt{6x - 1}}

    Substituting back t=6x1t = \sqrt{6x - 1}:

    dudx=11+(6x1)236x1=11+6x136x1=36x=12x\frac{du}{dx} = \frac{1}{1 + (\sqrt{6x - 1})^2} \cdot \frac{3}{\sqrt{6x - 1}} = \frac{1}{1 + 6x - 1} \cdot \frac{3}{\sqrt{6x - 1}} = \frac{3}{6x} = \frac{1}{2x}

    Hence,

    du=12xdxdu = \frac{1}{2x} dx

  2. Finding vv:

    dv=dx    v=xdv = dx \implies v = x

Now, applying the integration by parts formula:

arctan(6x1)dx=xarctan(6x1)x12xdx\int \arctan(\sqrt{6x - 1}) \, dx = x \arctan(\sqrt{6x - 1}) - \int x \cdot \frac{1}{2x} \, dx

Simplify the integral on the right-hand side:

x12xdx=12dx=12dx=12x\int x \cdot \frac{1}{2x} \, dx = \int \frac{1}{2} \, dx = \frac{1}{2} \int dx = \frac{1}{2} x

Putting it all together:

arctan(6x1)dx=xarctan(6x1)12x+C\int \arctan(\sqrt{6x - 1}) \, dx = x \arctan(\sqrt{6x - 1}) - \frac{1}{2} x + C

Therefore, the indefinite integral of arctan(6x1)\arctan(\sqrt{6x - 1}) is:

xarctan(6x1)12x+C\boxed{x \arctan(\sqrt{6x - 1}) - \frac{1}{2} x + C}

Would you like further details or have any questions?

Here are 5 more questions you might be interested in:

  1. How do you find the indefinite integral of e2xe^{2x}?
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  3. How do you solve the integral sin2(x)dx\int \sin^2(x) \, dx?
  4. What is the method of partial fractions in integration?
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Tip: Integration by parts is particularly useful for integrals involving products of functions, where you can identify one part to differentiate and another to integrate.

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Math Problem Analysis

Mathematical Concepts

Integration
Arctangent function
Integration by parts

Formulas

Integration by parts formula

Theorems

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Suitable Grade Level

College