Evaluate trig functions at infinity?

In summary, evaluating trig functions at infinity involves determining the value of a trigonometric function as the input approaches infinity. This is important for understanding the behavior of these functions in real-world applications. The most commonly evaluated trig functions at infinity are sine, cosine, and tangent, but other trig functions can also be evaluated in some cases. To evaluate a trig function at infinity, we use the concept of a limit and can also use mathematical techniques such as L'Hôpital's rule. Some misconceptions about evaluating trig functions at infinity include thinking that the value is always infinite and only considering positive infinity.
  • #1
AStaunton
105
1
is it meaningful to evaluate cos and sin at infinity? I ask in relation to Fourier integrals...

ie does cos(infinity) have a value
 
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  • #2
The improper integral of sin(x) or cos(x) from zero to inf does not converge or diverge
so you can't evaluate it.
 
  • #3
AStaunton said:
ie does cos(infinity) have a value

You tell me. What does the graph of cosine look like? Is cos(x) going to approach a certain number as x approaches infinity?
 

FAQ: Evaluate trig functions at infinity?

What is the definition of "Evaluate trig functions at infinity"?

The phrase "Evaluate trig functions at infinity" refers to the process of determining the value of a trigonometric function when the input (or angle) approaches infinity. This is often done using the concept of a limit, where the function is evaluated as the input becomes larger and larger.

Why is it important to evaluate trig functions at infinity?

Evaluating trig functions at infinity allows us to understand the behavior of these functions as the input approaches very large values. This can be useful in various real-world applications, such as predicting the behavior of waves or understanding the geometry of circles and ellipses.

What are the common trig functions that are evaluated at infinity?

The most frequently evaluated trig functions at infinity are sine, cosine, and tangent. However, other trig functions such as secant, cosecant, and cotangent can also be evaluated at infinity in some cases.

How do you evaluate trig functions at infinity?

To evaluate a trig function at infinity, we can use the concept of a limit. This involves plugging in very large values for the input and observing the behavior of the function as the input approaches infinity. We can also use mathematical techniques such as L'Hôpital's rule to evaluate indeterminate forms.

What are some common misconceptions about evaluating trig functions at infinity?

One common misconception is that the value of a trig function at infinity is always equal to infinity. In reality, the limit of a trig function at infinity may not always exist or may approach a finite value. Another misconception is that only positive infinity needs to be considered, when in fact, trig functions can also be evaluated at negative infinity.

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