Trigonometry
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Trigonometry
I must go down to the seas again, to the lonely sea and the sky,
And all I ask is a tall ship and a star to steer her by.
John Masefield
Trigonometry background
Angles of elevation and depression
The angle of elevation is the angle between the horizontal and a direction above
the horizontal (see figure 7.1). The angle of depression is the angle between the
horizontal and a direction below the horizontal (see figure 7.2).
Bearing
The bearing (or compass bearing) is the direction measured as an angle from
north, clockwise (see figure 7.3).
angle of elevation
Figure 7.1
angle of depression
Figure 7.2
150°
E
this direction is
a bearing of 150°
W
N
S
Figure 7.3