Defining a vector in magnitude,angle form.

I've learned that vectors can be defined in,basically, two ways. (1) Unit Vector Form (xi+yj+zk) (2)Magnitude angle form.
The second form always adds a confusion in problems. For instance let's define a function A and B as:
YzorQto.png


When we define -B why do we do it as follows:
pj8S94Y.png


I mean why do we write it as -B isn't the information of the direction clear from the angle between A and the Blue line?
 

SteamKing

Staff Emeritus
Science Advisor
Homework Helper
12,794
1,663
You may not always have a diagram to refer to, especially if your vector calculations get long and involved.
 

Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving

Hot Threads

Top