Skip to main content
Ch. 4 - Laws of Sines and Cosines; Vectors
Blitzer - Trigonometry 3rd Edition
Blitzer3rd EditionTrigonometryISBN: 9780137316601당신이 사용하는 게 아니라요?교과서 변경
4장, 문제 29

In Exercises 21–38, let u = 2i - 5j, v = -3i + 7j, and w = -i - 6j. Find each specified vector or scalar.
-4w

검증된 단계별 안내
1
Identify the given vector \( w = -\mathbf{i} - 6\mathbf{j} \), which can be written in component form as \( w = (-1, -6) \).
Understand that multiplying a vector by a scalar means multiplying each component of the vector by that scalar.
Set up the scalar multiplication: \( -4w = -4 \times (-1, -6) \).
Multiply each component of \( w \) by \( -4 \): \( -4 \times (-1) \) for the \( \mathbf{i} \) component and \( -4 \times (-6) \) for the \( \mathbf{j} \) component.
Write the resulting vector after multiplication as \( -4w = (4, 24) \), which corresponds to \( 4\mathbf{i} + 24\mathbf{j} \).

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
1m

주요 개념

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

Vector Representation in Component Form

Vectors in two dimensions can be expressed as a combination of unit vectors i and j, representing the x and y components respectively. For example, u = 2i - 5j means the vector has an x-component of 2 and a y-component of -5. Understanding this form allows for straightforward vector operations like addition, subtraction, and scalar multiplication.
추천 영상:
03:55
Position Vectors & Component Form

Scalar Multiplication of Vectors

Scalar multiplication involves multiplying each component of a vector by a scalar (a real number). This operation changes the magnitude of the vector without altering its direction if the scalar is positive, or reverses the direction if the scalar is negative. For instance, multiplying vector w by -4 scales and reverses w.
추천 영상:
05:05
Multiplying Vectors By Scalars

Vector Notation and Operations

Vectors are often denoted using unit vectors i and j for clarity in two dimensions. Operations like addition, subtraction, and scalar multiplication are performed component-wise. Recognizing how to manipulate vectors in this notation is essential for solving problems involving vector quantities.
추천 영상:
06:01
i & j Notation