Integration Techniques: Solving Tricky Problems with Tan Functions

  • Thread starter BLUE_CHIP
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In summary, a 16-year-old student is seeking help with integrating a function and is struggling to understand the concept. They provide the function [tex]I_n(x)=\int\limits_0^x \tan^n{{\theta}}{{d\theta}}[/tex] and ask for assistance in solving it. Another user offers a suggestion using a [tex]u=\tan\theta[/tex] substitution. A third user makes a rude comment about the 16-year-old's age, to which another user defends the student. The conversation ends with a user from India mentioning that calculus is a compulsory subject at the age of 17.
  • #1
BLUE_CHIP
Someone fix my tex pls...


I'm only 16 so i put this on the K-12 forum but they can't seem to help...

OK. I've had a little break from my studdies and need some help with this...

[tex]I_n(x)=\int\limits_0^x \tan^n{{\theta}}{{d\theta}},n\leq{0},{{x}}<\frac{\pi}{2}[\tex]

By writing [tex]\tan{\theta}[\tex] as [tex]\tan^{n-2}{\theta}\tan^2{\theta}[\tex], or otherwise, show that

[tex]I_n(x)=\frac{1}{n-1}\tan^{n-1}{x}-I_{n-2}(x), n\leq{2},x<\frac{\pi}{2}[\tex]

Hence evaluate [tex]\int\limits_{0}^{\frac{\pi}{3}}\tan^4{\thet
a}d\theta[\tex], leaving your answers in terms of [tex]\pi[\tex]

Thanks (Goddam further maths)
 
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  • #2
Originally posted by BLUE_CHIP
Someone fix my tex pls...


I'm only 16 so i put this on the K-12 forum but they can't seem to help...

OK. I've had a little break from my studdies and need some help with this...

[tex]I_n(x)=\int\limits_0^x \tan^n{{\theta}}{{d\theta}},n\leq{0},{{x}}<\frac{\pi}{2}[/tex]

By writing [tex]\tan{\theta}[/tex] as [tex]\tan^{n-2}{\theta}\tan^2{\theta}[/tex], or otherwise, show that

[tex]I_n(x)=\frac{1}{n-1}\tan^{n-1}{x}-I_{n-2}(x), n\leq{2},x<\frac{\pi}{2}[/tex]

Hence evaluate [tex]\int\limits_{0}^{\frac{\pi}{3}}\tan^4{\thet
a}d\theta[/tex], leaving your answers in terms of [tex]\pi[/tex]

Thanks (Goddam further maths)
 
  • #3
bulletin board commands like [ /tex ], get slashes. LaTeX commands get backslashes like \Sum

OK. here we go:

[tex]
\begin{gather*}
\tan^n \theta=\tan^{n-2}\theta \tan^2 \theta=\\
\tan^{n-2}\theta(\sec^2\theta-1)=\\
\tan^{n-2}\theta\sec^2\theta-\tan^{n-2}\theta
\end{gather*}
[/tex]

so

[tex]
\int\tan^2\theta\ d\theta=\int\tan^{n-2}\theta\sec^2\theta\ d\theta-\int\tan^{n-2}\theta\ d\theta[/tex]
use a [itex]u=\tan\theta[/tex] substitution and you have
[tex]
I_n(x)=\int^{u(x)} u^{n-2}\ du-I_{n-2}(x)[/tex]

and maybe you can take it from there?
 
Last edited:
  • #4
BLUE_CHIP: you're taking Further Maths at 16? as in the A-level subject? that's pretty impressive...
 
  • #5
Well, I'm taking the A-level this year but I had done all the single Maths before so my teacher said that we should start on P4 and P5 so HeyHo. Fun and games...
 
  • #6
heh that's cool. then you'll be like, a match for some of the more accelerated people in the US :P enjoy yourself.
 
  • #7
Lame, just another "Hey look I'm 16 and I'm integrating, but I don't know what to do, pls help and btw, I'm 16, say I'm cool pls" thread...

STFU pls. thanks.
 
  • #8
Originally posted by PrudensOptimus
Lame, just another "Hey look I'm 16 and I'm integrating, but I don't know what to do, pls help and btw, I'm 16, say I'm cool pls" thread...

STFU pls. thanks.

dude what is your problem? get off the guy's case. Seriously, so what if he mentions he's sixteen and integrating, for most people (excepting the true geniuses) that's something of an accomplishment. so lay off with being such an ass to someone just looking for help.
 
  • #9
actually integration in itself isn't particularly impressive (most people around me learn it at 16); in fact i just recalled that taking Further Math at 16-17 is actually normal and not exceptional, so i take my compliment back.

no offence blue_chip :)
 
  • #10
well i live in california, and here about 80 (out of 3000) students a year take AP calculus, while about 70% can't pass a test on simple algebra and geometry. So for this educationally challenged state it is something of an accomplishment. And even if it isn't its still no reason to go off on him.
 
  • #11
Well guys Here in India we have these kind of functions and problems when we are 17
and calculus is dominating feature. I must say it is compulsory here.
 

FAQ: Integration Techniques: Solving Tricky Problems with Tan Functions

What is the purpose of using tan functions in integration techniques?

Tan functions, also known as tangent functions, are commonly used in integration techniques because they can help solve tricky integration problems that involve trigonometric functions. By using tan functions, we can simplify the integration process and make it easier to solve complex problems.

How do you solve a tricky integration problem using tan functions?

To solve a tricky integration problem using tan functions, the first step is to identify the trigonometric function in the problem. Then, we can use the identity tan(x) = sin(x)/cos(x) to rewrite the function in terms of sin(x) and cos(x). From there, we can use integration techniques such as substitution or integration by parts to solve the problem.

Can you give an example of a tricky integration problem that can be solved using tan functions?

One example of a tricky integration problem that can be solved using tan functions is ∫(sec(x))^2 dx. By rewriting sec(x) as 1/cos(x), we can then use the substitution method and let u = cos(x). This will result in an integral with du and u terms, which can be easily solved. Finally, we can substitute back u for cos(x) to get the final solution.

Are there any other types of integration techniques that can be used for tricky problems?

Yes, there are other integration techniques that can be used for tricky problems, such as trigonometric identities, partial fractions, and inverse trigonometric functions. It is important to have a strong understanding of all these techniques in order to effectively solve complex integration problems.

Are there any limitations to using tan functions in integration techniques?

While tan functions can be useful in solving tricky integration problems, they may not always be the most efficient or practical method. In some cases, other integration techniques may be more suitable or result in a simpler solution. It is important to understand the strengths and limitations of each integration technique and choose the most appropriate one for each problem.

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