Integration of linear functions

In summary, it doesn't matter whether you use "c" or "25/4+ c" it still represents some arbitrary constant.
  • #1
sgstudent
739
3

Homework Statement


If i integrate (2x+5) using the simplest rule, i get x2+5x+c, however if i use the linear function method, i would get (2x+5)^2/4 +c so simplifying it i get (4x^2+20x+25)/4 +c=x^2+5x+25/4+c. So does it mean when i use the two different methods my constant,c is different?


Homework Equations


linear integration rule

The Attempt at a Solution


So does it mean when i use the two different methods my constant,c is different?
 
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  • #2
Yes, there's no meaningful difference there.
 
  • #3
thanks!
 
  • #4
sgstudent said:

Homework Statement


If i integrate (2x+5) using the simplest rule, i get x2+5x+c, however if i use the linear function method, i would get (2x+5)^2/4 +c so simplifying it i get (4x^2+20x+25)/4 +c=x^2+5x+25/4+c. So does it mean when i use the two different methods my constant,c is different?


Homework Equations


linear integration rule

The Attempt at a Solution


So does it mean when i use the two different methods my constant,c is different?
C is an arbitrary constant. It doesn't matter whether you use "c" or "25/4+ c" it still represents some arbitrary constant.

Suppose you were given that dy/dx= 2x+ 5 and that y(0)= 1. Clearly y is the integral of 2x+ 5 so, integrating the first way, you would get y(x)= x2+ 5x+ c and then the addtional condition, that y(0)= 1, becomes y(0)= 02+ 5(0)+ c= c= 1 so you answer is y(x)= x2+ 5x+ 1.

Integrating the second way, y(x)= x2+ 5x+ 25/4+ c so that y(0)= 02+ 5(0)+ 25/4+ c= 25/4+ x= 1 so that c= 1- 25/4= -21/4. But that means that y(x)= x2+ 5x+ 25/4- 21/4= x2+ 5x+ 4/4= x2+ 5x+ 1 just as before.
 
  • #5
sgstudent said:

Homework Statement


If i integrate (2x+5) using the simplest rule, i get x2+5x+c, however if i use the linear function method, i would get (2x+5)^2/4 +c so simplifying it i get (4x^2+20x+25)/4 +c=x^2+5x+25/4+c. So does it mean when i use the two different methods my constant,c is different?


Homework Equations


linear integration rule

The Attempt at a Solution


So does it mean when i use the two different methods my constant,c is different?

If I ever use a method of integration that gives me some constant such as +1 but then I also have a +c added on the end, I just merge them together to make it +c2 or +k or if the teacher isn't strict / doesn't care I'll just get rid of the 1.
 

1. What is the definition of integration of linear functions?

Integration of linear functions is the process of finding the area under a linear function on a given interval. It is the inverse operation of differentiation, and it involves finding the antiderivative of the function.

2. What is the purpose of integrating linear functions?

The purpose of integrating linear functions is to solve problems that involve finding the total amount or accumulated value of a changing quantity over a given time period. It is also used to find the average value of a function and to calculate displacement, velocity, and acceleration.

3. How do you integrate a linear function?

To integrate a linear function, you need to first find the antiderivative of the function. This involves using integration rules and techniques, such as the power rule, substitution, and integration by parts. Once you have found the antiderivative, you can then evaluate the integral at the given limits to find the area under the curve.

4. What is the difference between definite and indefinite integration of linear functions?

Definite integration of linear functions involves finding the area under the curve between two given limits. It results in a specific numerical value. Indefinite integration, on the other hand, involves finding the general form of the antiderivative of the function and does not involve evaluating at specific limits.

5. How is integration of linear functions used in real life?

Integration of linear functions is used in a variety of fields, such as physics, engineering, economics, and finance. It is used to calculate quantities such as displacement, velocity, acceleration, work, and profit. It is also used in the process of curve fitting, which is used to model and predict real-life data.

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