Finding domain of a trigonometric function

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Discussion Overview

The discussion revolves around finding the domain of the trigonometric function $$f(x) = \frac{1+x}{ e^{cos(x)}}$$. Participants explore the conditions under which the function is defined, focusing on the behavior of the denominator.

Discussion Character

  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • One participant initiates the discussion by stating the need to find the domain and setting the condition that $$e^{cos(x)} > 0$$.
  • Another participant agrees that the numerator is defined for all x and asserts that the denominator is always positive, as both $$cos(x)$$ and $$e^x$$ are defined for all x.
  • It is noted that the only potential issue for the domain could arise from the denominator being zero, but this is countered by the assertion that it does not happen anywhere.
  • There is a suggestion that the domain could be all real numbers, which is later affirmed by another participant.

Areas of Agreement / Disagreement

Participants generally agree that the function is defined for all real numbers, with no significant disagreement present in the discussion.

Contextual Notes

No limitations or unresolved mathematical steps are noted in the discussion.

Who May Find This Useful

Readers interested in mathematical reasoning related to function domains, particularly in the context of trigonometric and exponential functions.

tmt1
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I need to find the domain of this function:

$$f(x) = \frac{1+x}{ e^{cos(x)}}$$

I set $${ e^{cos(x)}}> 0$$

But I'm not sure what to do after this.
 
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tmt said:
I need to find the domain of this function:

$$f(x) = \frac{1+x}{ e^{cos(x)}}$$

I set $${ e^{cos(x)}}> 0$$

But I'm not sure what to do after this.

The top is obviously defined for all x.

The bottom, as you have established, is always positive. As both cos(x) and e^x are defined for all x, so is their composition.

So the top and bottom are defined for all x. The only place where the quotient of the two functions might not be defined is where the denominator is 0. But you already established that this doesn't happen anywhere.

So what is the domain of your function?
 
Prove It said:
The top is obviously defined for all x.

The bottom, as you have established, is always positive. As both cos(x) and e^x are defined for all x, so is their composition.

So the top and bottom are defined for all x. The only place where the quotient of the two functions might not be defined is where the denominator is 0. But you already established that this doesn't happen anywhere.

So what is the domain of your function?

All real numbers?
 
tmt said:
All real numbers?

Correct :)
 

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