Given the vector [tex]u[/tex] equal to [tex]2\left\langle \cos 95^{\circ}, \sin 95^{\circ} \right\rangle[/tex] and vector [tex]v[/tex] equal to [tex]4\left\langle \cos 165^{\circ}, \sin 165^{\circ} \right\rangle[/tex], find the sum [tex]u + v[/tex] and write your answer in magnitude and direction form with the magnitude rounded to the nearest tenth and the direction rounded to the nearest degree, [tex]0^{\circ} \leq \theta \ \textless \ 360^{\circ}[/tex].



Answer :

To find the sum of vectors [tex]\(u\)[/tex] and [tex]\(v\)[/tex] and express it in terms of magnitude and direction, we will follow these steps:

1. Decompose Each Vector into Components:

- Vector [tex]\(u\)[/tex] has a magnitude of 2 and an angle of 95 degrees.
- [tex]\(u_x = 2 \cos 95^\circ \)[/tex]
- [tex]\(u_y = 2 \sin 95^\circ \)[/tex]

- Vector [tex]\(v\)[/tex] has a magnitude of 4 and an angle of 165 degrees.
- [tex]\(v_x = 4 \cos 165^\circ \)[/tex]
- [tex]\(v_y = 4 \sin 165^\circ \)[/tex]

2. Compute the Components of Each Vector:

The components (x and y) for these vectors are:
[tex]\[ u_x = 2 \cos 95^\circ \\ u_y = 2 \sin 95^\circ \\ v_x = 4 \cos 165^\circ \\ v_y = 4 \sin 165^\circ \][/tex]

3. Sum the Corresponding Components:

Add the x-components and y-components separately:
[tex]\[ \text{resultant}_x = u_x + v_x \\ \text{resultant}_y = u_y + v_y \\ \][/tex]

4. Calculate the Magnitude of the Resultant Vector:

Use the Pythagorean theorem to find the magnitude [tex]\( R \)[/tex]:
[tex]\[ R = \sqrt{\text{resultant}_x^2 + \text{resultant}_y^2} \][/tex]

5. Find the Angle of the Resultant Vector:

Use the arctangent function to find the angle [tex]\( \theta \)[/tex]:
[tex]\[ \theta = \arctan\left(\frac{\text{resultant}_y}{\text{resultant}_x}\right) \][/tex]
Make sure the angle is in the correct quadrant based on the signs of [tex]\(\text{resultant}_x\)[/tex] and [tex]\(\text{resultant}_y\)[/tex], and convert from radians to degrees if necessary.

6. Normalize the Angle:

Ensure that [tex]\(0^\circ \leq \theta < 360^\circ\)[/tex].

After performing these calculations, we find:

- The magnitude of the resultant vector [tex]\( R \)[/tex] is approximately [tex]\(5.0\)[/tex], rounded to the nearest tenth.
- The direction of the resultant vector [tex]\( \theta \)[/tex] is approximately [tex]\(143^\circ\)[/tex], rounded to the nearest degree.

Therefore, the sum [tex]\( u + v \)[/tex] expressed in magnitude and direction form is:

[tex]\[ \boxed{5.0 \text{ units, direction } 143^\circ} \][/tex]