Select the correct answer.

Vector [tex]$u$[/tex] has its initial point at [tex]$(15, 22)$[/tex] and its terminal point at [tex][tex]$(5, -4)$[/tex][/tex]. Vector [tex]$v$[/tex] points in a direction opposite that of [tex]$u$[/tex], and its magnitude is twice the magnitude of [tex][tex]$u$[/tex][/tex]. What is the component form of [tex]$v$[/tex]?

A. [tex]v = \langle -20, 36 \rangle[/tex]
B. [tex]v = \langle -20, 52 \rangle[/tex]
C. [tex]v = \langle 20, 36 \rangle[/tex]
D. [tex]v = \langle 20, 52 \rangle[/tex]



Answer :

To solve this problem, let's start by finding the components of vector [tex]\( u \)[/tex].

1. Identify the initial and terminal points of vector [tex]\( u \)[/tex]:
[tex]\[ \text{Initial Point of } u: (15, 22) \][/tex]
[tex]\[ \text{Terminal Point of } u: (5, -4) \][/tex]

2. Calculate the components of vector [tex]\( u \)[/tex] by subtracting the coordinates of the initial point from the coordinates of the terminal point:
[tex]\[ u_x = 5 - 15 = -10 \][/tex]
[tex]\[ u_y = -4 - 22 = -26 \][/tex]
So, the component form of vector [tex]\( u \)[/tex] is:
[tex]\[ u = \langle -10, -26 \rangle \][/tex]

3. Calculate the magnitude of vector [tex]\( u \)[/tex]:
[tex]\[ \text{Magnitude of } u = \sqrt{(-10)^2 + (-26)^2} = \sqrt{100 + 676} = \sqrt{776} \approx 27.86 \][/tex]

4. Since vector [tex]\( v \)[/tex] points in the opposite direction of [tex]\( u \)[/tex] and has twice the magnitude, first, we determine the vector components for a vector that would have twice the magnitude of [tex]\( u \)[/tex]:
[tex]\[ \text{Magnitude of } v = 2 \times 27.86 = 55.72 \][/tex]

5. The components of vector [tex]\( v \)[/tex] are:
[tex]\[ v_x = -2 \times (-10) = 20 \][/tex]
[tex]\[ v_y = -2 \times (-26) = 52 \][/tex]

Therefore, the component form of [tex]\( v \)[/tex] is [tex]\( \langle 20, 52 \rangle \)[/tex].

The correct answer is:
[tex]\[ \boxed{D \quad v = \langle 20, 52 \rangle} \][/tex]