Book demonstration about trigonometric relations

In summary, the author is discussing an equation involving trigonometric identities. They state that their statements are correct and they want to prove something about the absolute value, which is why they took the absolute value of both sides. The other person is confused about the use of sine instead of cosine, but the author explains that it is the same thing since multiplication is commutative.
  • #1
Bunny-chan
105
4

Homework Statement


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[/B]

In the equation between [itex](3)[/itex] and [itex](2)[/itex], why does the author says that
4853327b00864221b28222f8ec109261.png
? Isn't the trigonometric identity actually
b1d600bf2773406fb9443fa8e18b6fac.png
?

2. Homework Equations

The Attempt at a Solution

 

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  • #2
You are right, but that doesn't mean that what they say is wrong. In fact it proves that their statements are correct. They want to prove something about the absolute value, so they took the absolute value of both sides.
 
  • #3
FactChecker said:
You are right, but that doesn't mean that what they say is wrong. In fact it proves that their statements are correct. They want to prove something about the absolute value, so they took the absolute value of both sides.
Sorry, I don't understand what you mean. How does it prove his statement is correct?

I wasn't wondering about the absolute values, I was confused about the fact that it should be two times the cosine, not the sine.
 
  • #4
Bunny-chan said:
Sorry, I don't understand what you mean. How does it prove his statement is correct?

I wasn't wondering about the absolute values, I was confused about the fact that it should be two times the cosine, not the sine.
It's the same thing. Multiplication is commutative. They just swapped the order of the multiplication.
 
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FAQ: Book demonstration about trigonometric relations

What is the purpose of a book demonstration about trigonometric relations?

The purpose of a book demonstration about trigonometric relations is to visually and practically explain the fundamental concepts and principles of trigonometry, including the relationships between angles and sides of a triangle, and how to use trigonometric functions to solve problems.

Who can benefit from a book demonstration about trigonometric relations?

Students, teachers, and anyone interested in learning or teaching trigonometry can benefit from a book demonstration about trigonometric relations. It can also be a helpful resource for those who need to refresh their understanding of trigonometry.

What topics are typically covered in a book demonstration about trigonometric relations?

Some common topics covered in a book demonstration about trigonometric relations include the basic trigonometric functions (sine, cosine, and tangent), the Pythagorean theorem, trigonometric identities, and solving for unknown angles and sides in right triangles.

Are there any prerequisites for understanding a book demonstration about trigonometric relations?

A basic understanding of algebra and geometry is recommended for understanding a book demonstration about trigonometric relations. Familiarity with basic trigonometric functions and their properties can also be helpful.

How can a book demonstration about trigonometric relations be useful in real-life situations?

Trigonometry has many practical applications in fields such as engineering, architecture, physics, and astronomy. A book demonstration about trigonometric relations can help individuals understand and apply these concepts in real-life situations, such as calculating heights of buildings or distances between objects.

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