Integral of f(x)=cos(x)/sqrt(1+x^2) - Get Help Here!

  • Context: Undergrad 
  • Thread starter Thread starter dvdstvns
  • Start date Start date
  • Tags Tags
    Integral
Click For Summary

Discussion Overview

The discussion revolves around the integral of the function f(x) = cos(x)/sqrt(1+x^2). Participants are seeking assistance in evaluating this integral, which is presented as part of a calculus problem. The scope includes both the evaluation of the integral and the properties of definite integrals.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant expresses difficulty in solving the integral, noting that online calculators indicate it may not exist or is too complex.
  • Another participant questions whether the integral is indefinite or definite, suggesting a possible typo in the problem statement.
  • A later post clarifies the full problem, presenting it as a definite integral from -1 to 1 and asking whether it is true that 0 ≤ ∫ from -1 to 1 of cos(x)/sqrt(1+x^2) dx.
  • One participant inquires about the sign of the function cos(x)/sqrt(1+x^2) over the interval [-1,1], suggesting that this could help in drawing conclusions about the integral.
  • Another participant claims to know the answer is true but is unsure how to demonstrate this through the integral, indicating a desire to show work.
  • One participant asserts that evaluating the integral is unnecessary to answer the question, implying that properties of definite integrals may provide the needed insights.
  • Another participant references the importance of properties of definite integrals and suggests applying these to the hint provided by a previous contributor.

Areas of Agreement / Disagreement

Participants generally agree that the integral is complex and may not be solvable in a straightforward manner. However, there is no consensus on how to approach the problem or whether the integral can be evaluated directly.

Contextual Notes

There are unresolved assumptions regarding the nature of the integral (indefinite vs. definite) and the properties of the function over the specified interval. The discussion also reflects uncertainty about the evaluation methods applicable to this integral.

dvdstvns
Messages
3
Reaction score
0
I need to solve for the integral of f(x)=cos(x)/sqrt(1+x^2)
Integral calculating computers online all say that this integral doesn't exist or takes too much computing time to solve. This is only a calculus 1 problem so I imagine if the answer is too complicated then it was probably a mistake on the professors part. Any help is greatly appreciated.
 
Physics news on Phys.org
Is the question asking for the indefinite or definite integral? I would guess that there is a typo if the only statement of the problem is [itex]\int\frac{\cos x}{\sqrt{1+x^2}}[/itex]
 
The full problem is:
True or false 0≤∫1-1 cos(x)/√1+x2

Mod edit: In a nicer format, this is
$$0 \leq \int_{-1}^1 \frac{cos(x)~dx}{\sqrt{1 + x^2}}$$[/color]
 
Last edited by a moderator:
How does cos(x)/√1+x2 look like in the interval [-1,1]? Is it positive or negative? You can perhaps conclude something based on that.
 
Well I know the answer to the problem is true, however, I'm trying to show the integral to show work, and I have no idea how to get the integral.
 
dvdstvns said:
Well I know the answer to the problem is true, however, I'm trying to show the integral to show work, and I have no idea how to get the integral.
You don't need to evaluate the integral to answer the question. In fact, you won't be able to evaluate the integral, either. The hint from disregardthat is a good place to start.
 
As Mark44 stated you won't solve this problem by solving this integral =(. Any decent calculus book should give you some useful properties of definite integrals and when order may be preserved. Apply that information to the hint, and you should be good to go!
 

Similar threads

  • · Replies 12 ·
Replies
12
Views
3K
  • · Replies 8 ·
Replies
8
Views
4K
  • · Replies 11 ·
Replies
11
Views
3K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 31 ·
2
Replies
31
Views
5K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 8 ·
Replies
8
Views
5K
  • · Replies 15 ·
Replies
15
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K