Evaluate the integral after figuring out the proper method to use

In summary, the conversation discusses the best method for solving the integral ∫ ((2t+3)^2)/t^2 dt, with the student initially considering using integration by parts but not feeling confident in their understanding of the concept. Another student suggests a simpler approach of multiplying out the numerator and then splitting it up for integration. The first student expresses gratitude for the help.
  • #1
Painguy
120
0

Homework Statement


∫ ((2t+3)^2)/t^2 dt


Homework Equations





The Attempt at a Solution


I figured that I would use integration by parts. The problem I'm having is that we haven't actually learned integration by parts, only the u substitution method. I went ahead and read the book on the proof and several examples, but its still a bit new to me so I'm not sure how to approach he problem.

u=1/t^2
du=-dt/3t^3

∫dv∫=(2t+3)^2 dt
v=(4t^3)/3 +6t^2 +9t

4t/3 +6+9/t - ∫ ((4t^3)/3 +6t^2 +9t)/t^3 dt

Is there a more straight forward way of solving this?
 
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  • #2
Painguy said:

Homework Statement


∫ ((2t+3)^2)/t^2 dt


Homework Equations





The Attempt at a Solution


I figured that I would use integration by parts. The problem I'm having is that we haven't actually learned integration by parts, only the u substitution method. I went ahead and read the book on the proof and several examples, but its still a bit new to me so I'm not sure how to approach he problem.

u=1/t^2
du=-dt/3t^3

∫dv∫=(2t+3)^2 dt
v=(4t^3)/3 +6t^2 +9t

4t/3 +6+9/t - ∫ ((4t^3)/3 +6t^2 +9t)/t^3 dt

Is there a more straight forward way of solving this?

Sure there is. Just multiply the numerator out. Then split it up and integrate.
 
  • #3
Dick said:
Sure there is. Just multiply the numerator out. Then split it up and integrate.

Oh wow... Thanks for the help. I feel a little silly right now.
 

FAQ: Evaluate the integral after figuring out the proper method to use

1. What is the purpose of evaluating an integral?

Evaluating an integral allows us to find the exact numerical value of the area under a curve or the total accumulation of a function over a given interval. It is an important tool in solving various mathematical and scientific problems.

2. How do I know which method to use when evaluating an integral?

The method used to evaluate an integral depends on the type of function and the form of the integral. Some common methods include substitution, integration by parts, and trigonometric substitution. It is important to carefully analyze the integral and choose the appropriate method based on its structure.

3. Can I use a calculator to evaluate an integral?

Yes, there are many calculators and software programs that can evaluate integrals numerically. However, it is important to understand the underlying concepts and methods used in evaluating integrals in order to properly interpret and utilize the results.

4. What is the difference between definite and indefinite integrals?

A definite integral has specific limits of integration and results in a single numerical value, representing the exact area or accumulation over a given interval. An indefinite integral does not have limits of integration and results in a function, representing the family of curves that have the given function as their derivative.

5. Are there any special cases when evaluating an integral?

Yes, there are some special cases that may require different methods or techniques when evaluating an integral. These include improper integrals, trigonometric integrals, and integrals involving special functions such as logarithmic or exponential functions. It is important to be familiar with these special cases and their corresponding methods in order to accurately evaluate the integral.

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