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hover
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I've heard that there are some types of functions that are impossible to integrate. Can I see an example and why so?
Thanks!
Thanks!
hover said:I've heard that there are some types of functions that are impossible to integrate. Can I see an example and why so?
Thanks!
Anonymous217 said:It's e^{-x^2}, not e^{x^2}. Just correcting a typo most likely.
FallenRGH said:It's not that they are impossible to integrate, but rather their anti derivative cannot be defined by an elementary function( for example, the integral of ex2 or the integral of sin(x2). They can however be approximated if they are definite integrals using a Riemann sum, or using more complex methods of integration(for example with sin(x2) using the Fresnel Integral).
hover said:My calc book says that you can integrate elementary functions. Just out of curiosity, how can you tell when you don't have an elementary function?
Gib Z said:In general humans are not able to tell. There is something called the Risch algorithm that finds out if elementary antiderivatves exist, but its complex. So much so the full version of the algorithm has never been programmed onto a computer, though it is theoretically possible to do so.
Char. Limit said:One way to find a function that isn't integrable is, perhaps, to find a function that is nowhere differentiable. Its derivative (aside from being an impossibility) is not integrable.
If that's in response to my post, what I said is closer to (but not exactly the same as) "if the smallest sum of areas of big rectangles is not equal to the biggest sum of areas of small rectangles., then the function is not Riemann integrable". The main difference between that and what I said is that the "smallest" member of a set doesn't always exist. For example, what is the smallest member of the set of all x such that 1<x<2? That's why we talk about the greatest lower bound instead. (For the set I used as an example, it's =1). Same thing with "biggest" and "least upper bound".crd said:the way i translated it was "if the area of the smallest big rectangle is not equal to the area of the biggest small rectangle, then the function is not Riemann integrable"
sEsposito said:I'm pretty sure that it's going to be hard to actually find a function that is 100% not integrable.
the functions like ' sinx/x , tan rootx,hover said:I've heard that there are some types of functions that are impossible to integrate. Can I see an example and why so?
Thanks!
For a problem to be impossible to integrate means that it cannot be solved using standard mathematical integration techniques. This could be due to the complexity of the problem or the lack of a closed-form solution.
Functions that are impossible to integrate include those that do not have an antiderivative, those that are infinitely oscillating, and those that involve special functions such as the Gamma function or the Error function.
Yes, numerical methods such as the trapezoidal rule or Simpson's rule can be used to approximate the value of an integral for functions that are impossible to integrate analytically. However, this may not provide an exact solution and may be computationally intensive.
There are certain techniques that can be used to solve specific types of impossible integration problems, such as using integration by parts or substitution. However, these may not work for all problems and may require a deep understanding of advanced mathematical concepts.
Unfortunately, there is no definitive way to determine if a problem is impossible to integrate. It often requires trial and error or a deep understanding of the problem and mathematical techniques. If you are struggling to find an analytical solution, it may be best to use numerical methods or seek assistance from a more experienced mathematician.