The indefinite integral and its "argument"

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The discussion focuses on the indefinite integral and the concept of function arguments, specifically using examples like cos(x^2) and e^(tan(x)). It clarifies that in the case of cos(x^2), the argument is x^2, while for e^(tan(x)), the argument is tan(x). Both functions can be expressed in the form f(g(x)), where f is the outer function and g is the inner function. The participants explore how to integrate these functions and question the process if both functions are to be integrated simultaneously. The conversation emphasizes understanding the arguments of functions when setting up integrals.
Michael Santos
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Homework Statement


The indefinite integral $$\int \, $$ and it's argument.
The indefinite integral has a function of e.g ## \cos (x^2) \ ## or ## \ e^{tan (x)} \ ##
If the argument of ## \cos (x^2) \ ## is ## \ x^2 \ ## then the argument of ## \ e^{tan(x)} \ ## is ## \ x \ ## or ## \ tan (x) \ ## ?

Homework Equations

The Attempt at a Solution

 
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Hi,

Both are examples of the kind ##f\left( g(x)\right)\ ##.

The argument for ##f()##, the cosine function ##\cos()##, is ##x^2##, so ##g(x) = x^2##.

Similarly, the argument for exponentiation ## f() = \exp() \ ## is ##g(x) = \tan(x)##.

The integrand in both cases is ##f##, so you integrate ##\int f(g(x)) \, dx ##
 
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BvU said:
Hi,

Both are examples of the kind ##f\left( g(x)\right)\ ##.

The argument for ##f()##, the cosine function ##\cos()##, is ##x^2##, so ##g(x) = x^2##.

Similarly, the argument for exponentiation ## f() = \exp() \ ## is ##g(x) = \tan(x)##.

The integrand in both cases is ##f##, so you integrate ##\int f(g(x)) \, dx ##
What if both functions are to be integrated
BvU said:
Hi,

Both are examples of the kind ##f\left( g(x)\right)\ ##.

The argument for ##f()##, the cosine function ##\cos()##, is ##x^2##, so ##g(x) = x^2##.

Similarly, the argument for exponentiation ## f() = \exp() \ ## is ##g(x) = \tan(x)##.

The integrand in both cases is ##f##, so you integrate ##\int f(g(x)) \, dx ##
If both functions are to be integrated what is the argument to integrate?
 
Michael Santos said:
What if both functions are to be integrated
? Can you write the form of the integral that you mean ?
 
First, I tried to show that ##f_n## converges uniformly on ##[0,2\pi]##, which is true since ##f_n \rightarrow 0## for ##n \rightarrow \infty## and ##\sigma_n=\mathrm{sup}\left| \frac{\sin\left(\frac{n^2}{n+\frac 15}x\right)}{n^{x^2-3x+3}} \right| \leq \frac{1}{|n^{x^2-3x+3}|} \leq \frac{1}{n^{\frac 34}}\rightarrow 0##. I can't use neither Leibnitz's test nor Abel's test. For Dirichlet's test I would need to show, that ##\sin\left(\frac{n^2}{n+\frac 15}x \right)## has partialy bounded sums...