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Ch. 1 - Functions
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077당신이 사용하는 게 아니라요?교과서 변경
1장, 문제 1.3.54

Solving Trigonometric Equations


For Exercises 51–54, solve for the angle θ, where 0 ≤ θ ≤ 2π.


sin² θ = cos² θ

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1
Start by recognizing the given equation: sin² θ = cos² θ. This can be rewritten using the identity sin² θ + cos² θ = 1.
Rearrange the identity to express one trigonometric function in terms of the other: sin² θ = 1 - cos² θ.
Substitute this expression into the original equation: 1 - cos² θ = cos² θ.
Combine like terms to form a single equation: 1 = 2cos² θ.
Solve for cos² θ by dividing both sides by 2, then take the square root to find the possible values of cos θ. Consider the range 0 ≤ θ ≤ 2π to determine the specific angles that satisfy the equation.

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이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
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주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Trigonometric Identities

Trigonometric identities are equations that involve trigonometric functions and are true for all values of the variables involved. A key identity relevant to the given equation is the Pythagorean identity, which states that sin² θ + cos² θ = 1. Understanding these identities is crucial for simplifying and solving trigonometric equations.
추천 영상:
7:17
Verifying Trig Equations as Identities

Solving Trigonometric Equations

Solving trigonometric equations involves finding the angles that satisfy the equation within a specified interval. In this case, we need to manipulate the equation sin² θ = cos² θ to find the values of θ between 0 and 2π. Techniques often include using identities, factoring, and applying inverse trigonometric functions.
추천 영상:
5:02
Solving Logarithmic Equations

Unit Circle

The unit circle is a fundamental concept in trigonometry that provides a geometric interpretation of the sine and cosine functions. It is a circle with a radius of one centered at the origin of a coordinate plane. Understanding the unit circle helps in determining the angles corresponding to specific sine and cosine values, which is essential for solving the equation sin² θ = cos² θ.
추천 영상:
5:10
Evaluate Composite Functions - Values on Unit Circle