Simplifying this derivative....

In summary, the conversation discusses the evaluation of the derivative of a function using the chain rule. The correct answer is given by the book as F'(w)=(-4w)/sqrt(1-4w^(2)) due to the simplification of inverse trigonometric functions. The conversation ends with the clarification that sin and sin^-1 disappear because they are inverse functions.
  • #1
Jess Karakov
11
3

Homework Statement


Evaluate the derivative of the following function:
f(w)= cos(sin^(-1)2w)

Homework Equations


Chain Rule
eq0008M.gif


The Attempt at a Solution


I did just as the chain rule says where
F'(w)= -[2sin(sin^(-1)2w)]/[sqrt(1-4w^(2))

but the book gave the answer as F'(w)=(-4w)/sqrt(1-4w^(2))

and I'm wondering if there is some kind of simplification I'm missing. Why would sin and sin^(-1) disappear?
 
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  • #2
Jess Karakov said:

Homework Statement


Evaluate the derivative of the following function:
f(w)= cos(sin^(-1)2w)

Homework Equations


Chain Rule
View attachment 206165

The Attempt at a Solution


I did just as the chain rule says where
F'(w)= -[2sin(sin^(-1)2w)]/[sqrt(1-4w^(2))

but the book gave the answer as F'(w)=(-4w)/sqrt(1-4w^(2))

and I'm wondering if there is some kind of simplification I'm missing. Why would sin and sin^(-1) disappear?

Because they are inverse functions. ##\sin(\sin^{-1}(x))=x##.
 
  • Like
Likes Jess Karakov
  • #3
Dick said:
Because they are inverse functions. ##\sin(\sin^{-1}(x))=x##.
Ah okay. I wasn't aware of this. Thank you.
 

What is a derivative and why is it important?

A derivative is a mathematical concept that represents the rate of change of a function at a specific point. It is important in many fields of science, such as physics and engineering, as it helps to analyze and understand the rate at which quantities change over time.

How do I simplify a derivative?

To simplify a derivative, you can use basic algebraic rules and properties, such as the power rule, product rule, and chain rule. These rules allow you to break down a complex derivative into simpler parts, making it easier to solve and understand.

Can I use a calculator to simplify a derivative?

Yes, most scientific and graphing calculators have built-in functions for finding derivatives. However, it is still important to understand the basic rules and concepts behind derivatives to ensure the accuracy of your calculations.

What are some common mistakes made when simplifying derivatives?

Some common mistakes include forgetting to use the correct rules, missing negative signs, and not simplifying fully. It is also important to carefully evaluate the domain of the function to ensure that the derivative is defined at the point of interest.

How can derivatives be applied in real-world situations?

Derivatives have many real-world applications, such as in physics to calculate velocity and acceleration, in economics to analyze supply and demand, and in biology to model population growth. They are also used in optimization problems to find the maximum or minimum value of a function.

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