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Calculate The Integral 1x2 11x 28dx

Reviewed by Calculator Editorial Team

This guide explains how to calculate the definite integral of the function 1/x² + 11x - 28 with respect to x. We'll cover the mathematical steps, provide an interactive calculator, and explain how to interpret the results.

How to Calculate the Integral

Calculating the integral of 1/x² + 11x - 28 involves breaking the function into its component parts and integrating each term separately. Here's the step-by-step process:

  1. Identify the antiderivative for each term in the integrand.
  2. Combine the antiderivatives to form the general antiderivative.
  3. Apply the limits of integration to find the definite integral.

The antiderivative of 1/x² is -1/x, the antiderivative of 11x is 11x²/2, and the antiderivative of -28 is -28x. Combining these gives the general antiderivative: -1/x + 11x²/2 - 28x + C, where C is the constant of integration.

The Formula

The definite integral from a to b of (1/x² + 11x - 28) dx is calculated as:

∫[a,b] (1/x² + 11x - 28) dx = [-1/x + 11x²/2 - 28x] evaluated from a to b

This formula represents the area under the curve of the function between the specified limits. The result will depend on the values of a and b you choose.

Worked Example

Let's calculate the integral from x=1 to x=2:

  1. Evaluate the antiderivative at x=2: -1/2 + 11(4)/2 - 56 = -0.5 + 22 - 56 = -34.5
  2. Evaluate the antiderivative at x=1: -1 + 11(1)/2 - 28 = -1 + 5.5 - 28 = -23.5
  3. Subtract the lower limit from the upper limit: -34.5 - (-23.5) = -11

The integral from 1 to 2 of (1/x² + 11x - 28) dx is -11.

Interpreting the Result

The negative result indicates that the area under the curve is below the x-axis between the limits. The magnitude of the result represents the total area, regardless of direction.

Note: The integral is undefined at x=0 because 1/x² becomes infinite. Always ensure your limits of integration do not include x=0.

Frequently Asked Questions

What does the integral represent?

The integral represents the signed area under the curve of the function between the specified limits. A negative result indicates the area is below the x-axis.

Can I calculate the integral without limits?

Yes, the antiderivative is -1/x + 11x²/2 - 28x + C, where C is the constant of integration. For definite integrals, you need both upper and lower limits.

What if my limits include x=0?

The integral is undefined at x=0 because 1/x² becomes infinite. Choose limits that exclude x=0 to get a valid result.