Calculate The Integral 1x2 11x 28dx
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:
- Identify the antiderivative for each term in the integrand.
- Combine the antiderivatives to form the general antiderivative.
- 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:
- Evaluate the antiderivative at x=2: -1/2 + 11(4)/2 - 56 = -0.5 + 22 - 56 = -34.5
- Evaluate the antiderivative at x=1: -1 + 11(1)/2 - 28 = -1 + 5.5 - 28 = -23.5
- 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.