Derivative of a trig. function

In summary, we are trying to find the derivative of the function sinθ/2 + c/θ, which involves using the power rule or product rule. After discussing the role of c as a variable or constant in the question, we determine that the correct solution is (cosθ/2 - c/θ^2).
  • #1
frosty8688
126
0
1. Find the derivative of the function using the power rule or product rule



2. sinθ/2 + c/θ



3. I tried to do plus or minus the √1-cosθ/2
 
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  • #2
Your question is ambiguous. Please use parentheses. It looks like that want to find the derivative of
[tex]\frac{\sin \theta}{2} + \frac{c}{\theta}[/tex]
 
  • #3
Yes, that's it
 
  • #4
There is no need to plus or minus the √1-cosθ/2, simply find the derivative of sin θ and 1/θ w.r.t θ (I suppose that's what you are asked.) And what about c? How is it defined in the question?
 
  • #5
Here's what I have (cosθ/2) + (c/θ). c is a variable.
 
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  • #6
The c probably stands for some constant.
 
  • #7
ok, thanks.
 
  • #8
frosty8688 said:
Here's what I have (cosθ/2) + (c/θ). c is a variable.
If c is a constant, and the above is your solution attempt, then you have to do something with the 2nd term (ie. the derivative of c/θ isn't c/θ).
 
  • #9
The solution would be (cosθ/2).
 
  • #10
frosty8688 said:
The solution would be (cosθ/2).

No, how do you get this? What's the derivative of 1/θ?
 
  • #11
The derivative of a constant is 0.
 
  • #12
frosty8688 said:
The solution would be (cosθ/2).
Sorry, that's wrong. If the original problem was this:
[tex]\frac{\sin \theta}{2} + c[/tex]
(with c as a constant), then your answer would be right. But the 2nd term has a θ in the denominator. What do we do?
 
  • #13
It would be (cosθ/2 - c/θ^2)
 
  • #14
frosty8688 said:
It would be (cosθ/2 - c/θ^2)

Looks good.
 

FAQ: Derivative of a trig. function

1. What is the derivative of a trigonometric function?

The derivative of a trigonometric function is the rate of change of the function at a specific point. It represents the slope of the tangent line to the graph of the function at that point.

2. How do you find the derivative of a trigonometric function?

To find the derivative of a trigonometric function, you can use the general derivative formula for trigonometric functions, or you can use trigonometric identities to simplify the function before taking the derivative.

3. What is the chain rule and how does it apply to the derivative of a trigonometric function?

The chain rule is a derivative rule that allows us to find the derivative of composite functions. It applies to the derivative of a trigonometric function when the function is composed with another function, such as sin(x^2). In this case, the chain rule tells us to multiply the derivative of the outer function (sin) by the derivative of the inner function (x^2).

4. Can you give an example of finding the derivative of a trigonometric function using the chain rule?

Yes, for example, if we have the function f(x) = sin(x^2), we can use the chain rule to find its derivative. The derivative of the outer function sin(x^2) is cos(x^2), and the derivative of the inner function x^2 is 2x. Therefore, the derivative of f(x) is f'(x) = cos(x^2) * 2x = 2x cos(x^2).

5. What is the derivative of the inverse trigonometric functions?

The derivative of the inverse trigonometric functions can be found using the inverse function rule. For example, the derivative of arcsin(x) is 1/sqrt(1-x^2), and the derivative of arccos(x) is -1/sqrt(1-x^2). The derivatives of the other inverse trigonometric functions (arctan, arccot, arcsec, arccsc) can be similarly found using the inverse function rule.

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