Math Problem Statement

Calculate the following definite integral \( \int_0^{1/2} \sin(2\pi x) \, dx \).

Solution

To solve the given integral:

01/2sin(2πx)dx\int_0^{1/2} \sin(2\pi x) \, dx

we can proceed as follows:

Step 1: Set up the Integral

The integral is:

01/2sin(2πx)dx\int_0^{1/2} \sin(2\pi x) \, dx

Step 2: Integrate sin(2πx)\sin(2\pi x)

The antiderivative of sin(2πx)\sin(2\pi x) with respect to xx is:

12πcos(2πx)-\frac{1}{2\pi} \cos(2\pi x)

So, we have:

sin(2πx)dx=12πcos(2πx)\int \sin(2\pi x) \, dx = -\frac{1}{2\pi} \cos(2\pi x)

Step 3: Apply the Limits

Now we evaluate this from x=0x = 0 to x=12x = \frac{1}{2}:

01/2sin(2πx)dx=[12πcos(2πx)]01/2\int_0^{1/2} \sin(2\pi x) \, dx = \left[ -\frac{1}{2\pi} \cos(2\pi x) \right]_0^{1/2}

Substitute x=12x = \frac{1}{2} and x=0x = 0:

  1. For x=12x = \frac{1}{2}: 12πcos(2π12)=12πcos(π)=12π(1)=12π-\frac{1}{2\pi} \cos\left(2\pi \cdot \frac{1}{2}\right) = -\frac{1}{2\pi} \cos(\pi) = -\frac{1}{2\pi} \cdot (-1) = \frac{1}{2\pi}

  2. For x=0x = 0: 12πcos(2π0)=12πcos(0)=12π1=12π-\frac{1}{2\pi} \cos(2\pi \cdot 0) = -\frac{1}{2\pi} \cos(0) = -\frac{1}{2\pi} \cdot 1 = -\frac{1}{2\pi}

Step 4: Calculate the Result

Now, we subtract the values:

12π(12π)=12π+12π=1π\frac{1}{2\pi} - \left(-\frac{1}{2\pi}\right) = \frac{1}{2\pi} + \frac{1}{2\pi} = \frac{1}{\pi}

Final Answer:

The correct answer is:

1π\boxed{\frac{1}{\pi}}

So, the correct option is d. 1π\text{d. } \frac{1}{\pi}.

Would you like more details on this solution, or do you have any questions?

Related Questions:

  1. How do we find the antiderivative of trigonometric functions like sin\sin and cos\cos?
  2. Why does cos(π)\cos(\pi) equal 1-1?
  3. How does the Fundamental Theorem of Calculus apply to definite integrals?
  4. What are the basic properties of definite integrals over symmetric intervals?
  5. How would the result change if the limits of integration were different?

Tip: Remember that trigonometric integrals often involve using the antiderivatives of sin\sin and cos\cos, which are cos(x)-\cos(x) and sin(x)\sin(x), respectively.

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Math Problem Analysis

Mathematical Concepts

Calculus
Definite Integral
Trigonometric Integration

Formulas

Antiderivative of \( \sin(ax) = -\frac{1}{a} \cos(ax) \)
Fundamental Theorem of Calculus

Theorems

Fundamental Theorem of Calculus

Suitable Grade Level

Grades 11-12