Chapter 2: Vectors

2.4 Vectors and trig

Notice that the x and y components of a vector are at right angles to each other, and the magnitude of the vector makes the hypotenuse of the triangle. We can use trig functions and the Pythagorean theorem!

It is common practice to give the direction as an angle between 0° and 90°, along with a reference axis and direction of measurement. For example, consider an angle that is 150° when measured counterclockwise from the +x axis (which is the standard way of measuring angles in a math class). This same angle could be described as 30° when measured clockwise from the -x axis, or 60° measured counterclockwise from the +y axis.

Practice 2.3

Practice 2.4

Practice 2.5

Practice 2.6

Practice 2.7