What is the Integral of 9/(3e^-6x + 3e^6x)?

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In summary, the student is stuck trying to integrate a function 9/(3e^-6x + 3e^6x) and is at a loss. They try using u-substitutions but are not successful. They come up with a solution to integrate the function using inverse trigonometric functions and arctan().
  • #1
Suitengu
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Homework Statement



integrate 9/(3e^-6x + 3e^6x)


The Attempt at a Solution



integral :- the integral sign

integral [ (9/3)(1/e^6x + e^6x)]

3*integral [ 1/((1+e^12x)/e^6x)]

3*integral [ (e^6x)/(1+e^12x)]

Im stuck there. I thought I would get to something which I could integrate but I am at a loss.
 
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  • #2
Suitengu said:
3*integral [ (e^6x)/(1+e^12x)] dx

Im stuck there. I thought I would get to something which I could integrate but I am at a loss.

It looks like it's time for a u-substitution! What could you use for u that would leave you with an integral you'd know how to do?
 
  • #3
I don't think that anything works as I did see that route as well. As a matter of fact the only thing i saw was u = 1 +e^12x but that does work as the derivative of that is 12e^12x which is not in the numerator and from what I see, I doubt I can arrange the numerator to look like that.
 
  • #4
Suitengu said:
I don't think that anything works as I did see that route as well. As a matter of fact the only thing i saw was u = 1 +e^12x but that does work as the derivative of that is 12e^12x which is not in the numerator and from what I see, I doubt I can arrange the numerator to look like that.

In using u-substitutions, you don't always want to swallow the entire denominator in one bite. Try u = e^(6x) ...
 
  • #5
O.O. whoops you are right. then that would be

u = e^6x
du = 6e^6x dx

3*(1/6)*integral [1/(1+u^2)] which is a inverse trig integral.

(1/2)*arctan(u)

(1/2)*arctan(e^6x)

aright thanks man. How do I signal that I have gotten help and found a solution again?
 
  • #6
Suitengu said:
O.O. whoops you are right. then that would be

u = e^6x
du = 6e^6x dx

3*(1/6)*integral [1/(1+u^2)] which is a inverse trig integral.

(1/2)*arctan(u)

(1/2)*arctan(e^6x)

aright thanks man. How do I signal that I have gotten help and found a solution again?

...and don't forget the +C . ;-) (I always mention this because I've seen students get dinged on homework and exams for leaving that off of indefinite integral results.)

As the OP, you can edit the title of your thread. The custom here is to add '[SOLVED]' at the beginning of the title.

The u-substitution method is pretty versatile and can be applied in sometimes surprising situations. It can be a good idea to practice as many types of integrals in that section of your book/course as you can spare time for, in order to get experience with some of the kinds of substitutions you should be alert for.
 
  • #7
nice problem, ima borrow it if you don't mind ;)
 
  • #8
yeah don't worry I am a quite apt person when it comes to these things and it seems i had just forgotten how versatile as you said it is. and as for the C, i was lacerated badly by a teacher for leaving it off and haven't done it since so i am good. thanks to one and all again.
 

Related to What is the Integral of 9/(3e^-6x + 3e^6x)?

1. What is the purpose of the integration of 9/(3e^-6x + 3e^6x)?

The purpose of integrating 9/(3e^-6x + 3e^6x) is to find the area under the curve represented by the function. This is useful in many fields of science, such as physics, chemistry, and engineering, where the integration of a function can provide valuable information about the behavior of a system.

2. How do you solve the integration of 9/(3e^-6x + 3e^6x)?

To solve the integration of 9/(3e^-6x + 3e^6x), you can use the substitution method. Let u = 3e^-6x, then du = -18e^-6x dx. This allows us to rewrite the integral as 9/(-18u + 3u) = 3/(2u), which can be easily integrated. After integrating, substitute back in u to get the final answer.

3. Can the integration of 9/(3e^-6x + 3e^6x) be solved using other methods?

Yes, there are other methods that can be used to solve this type of integral, such as integration by parts or the use of trigonometric substitutions. However, the substitution method is the most straightforward and efficient method for solving this particular integral.

4. What are the limits of integration for 9/(3e^-6x + 3e^6x)?

The limits of integration for 9/(3e^-6x + 3e^6x) will depend on the specific problem you are trying to solve. In general, the limits of integration will be determined by the range of values for x that are relevant to the problem at hand.

5. How can the integration of 9/(3e^-6x + 3e^6x) be applied in real-world situations?

The integration of 9/(3e^-6x + 3e^6x) can be applied in many real-world situations, such as calculating the amount of drug in a patient's bloodstream over time, determining the rate of radioactive decay in a sample, or finding the work done by a varying force. In general, any situation where you need to find the area under a curve can be solved using integration.

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