Skip to main content
Ch. 7 - Applications of Trigonometry and Vectors
Lial - Trigonometry 12th Edition
Lial12th EditionTrigonometryISBN: 9780136552161당신이 사용하는 게 아니라요?교과서 변경
8장, 문제 19

For each pair of vectors u and v with angle θ between them, sketch the resultant.


|u| = 12, |v| = 20, θ = 27°

검증된 단계별 안내
1
Identify the given information: the magnitudes of vectors \( \mathbf{u} \) and \( \mathbf{v} \) are \( |\mathbf{u}| = 12 \) and \( |\mathbf{v}| = 20 \), and the angle between them is \( \theta = 27^\circ \).
Recall that the resultant vector \( \mathbf{R} = \mathbf{u} + \mathbf{v} \) can be found using the Law of Cosines for vectors, where the magnitude of \( \mathbf{R} \) is given by: \[ |\mathbf{R}| = \sqrt{|\mathbf{u}|^2 + |\mathbf{v}|^2 + 2 |\mathbf{u}| |\mathbf{v}| \cos(\theta)} \]
To sketch the resultant, start by drawing vector \( \mathbf{u} \) with length proportional to 12 units in any direction you choose.
Next, from the tip of \( \mathbf{u} \), draw vector \( \mathbf{v} \) at an angle of \( 27^\circ \) relative to \( \mathbf{u} \), with length proportional to 20 units.
The resultant vector \( \mathbf{R} \) is then drawn from the tail of \( \mathbf{u} \) (the starting point) to the tip of \( \mathbf{v} \) (the ending point). This vector represents the sum \( \mathbf{u} + \mathbf{v} \).

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
도움이 되었나요?

주요 개념

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

Vector Addition

Vector addition involves combining two vectors to find their resultant by placing them head-to-tail and drawing the vector from the start of the first to the end of the second. This graphical method helps visualize the resultant vector's magnitude and direction.
추천 영상:
05:29
Adding Vectors Geometrically

Law of Cosines for Vectors

The Law of Cosines relates the magnitudes of two vectors and the angle between them to find the magnitude of their resultant: |R| = √(|u|² + |v|² + 2|u||v|cosθ). This formula is essential for calculating the exact length of the resultant vector.
추천 영상:
가이드 코스
4:35
Intro to Law of Cosines

Angle Between Vectors

The angle θ between two vectors determines how they combine. It affects both the magnitude and direction of the resultant vector, influencing whether the vectors reinforce or partially cancel each other.
추천 영상:
04:33
Find the Angle Between Vectors