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What is the magnitude and direction of -(3.7+7.4)?

User Asad Rao
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1 Answer

5 votes

Complete question is;

What is the magnitude and direction of (-3.7i) + (7.4j)?

Answer:

Magnitude = 8.27

Direction = 116.57°

Explanation:

Magnitude of the vector will be;

|R| = √((-3.7²) + (7.4²))

|R| = √68.45

|R| = 8.27

Direction will be;

tan θ = 7.4/-3.7

tan θ = -2

θ = tan^(-1) -2

θ = -63.43°

Angle is negative but we can't present it as such.

Now, in the second and fourth quadrants, tan θ has a negative value.

However, from the components of the vector we are given, we see that we work here in the 2nd quadrant since the i vector is negative and j vector is positive. Therefore, a reference angle of 63.43° means that the actual angle is 63.43° above the negative x axis and can be written in standard form as;

180 − 63.43 = 116.57°

User Palak Bhansali
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4.9k points