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UNIT 1 : Fundamentals of trigonometry1.1 Trigonometric concepts
The word trigonometry is derived from two
Greek words: Trigon, which means
triangle, and metric, which means measure.
Trigonometry is the study of how the sides
and angles of a triangle are related to each
other.
Angles are named according to where their
terminal side lies,
The x-axis and y-axis divide a plane into four
quadrants as follow.
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A rotation angle is formed by an initial side through an angle, about a fixed
point called vertex, to terminal position called terminal side.
Example 1:
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Example 2:
Solution:
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Example 3:
Solution:
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Measure of an angle
a) Sexagesimal system
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Example 4:
Degrees, minutes second:
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Example 5:
Solution:
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Example 6:
Solution:
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b) Centesimal system
Example 7:
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c) Radian
When a central angle intercepts an arc that has the same length as a radius of the
circle, the measure of the angle is defined to de one radian.
Like degrees, radian measures the amount of the rotation from the initial side to
the terminal side of an angle.
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Proportions between three units
360 degrees=400grades, 180degrees=200grages
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Example 8:
Solution:
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Example 9:
Solution:
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Unit circle
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1.1 Trigonometric concepts Trigonometric ratios of acute angles
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1.1 Trigonometric concepts Examples 10:
Solution:
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1.1 Trigonometric concepts Examples 11:
Solution:
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1.1 Trigonometric concepts Examples 12:
Solution:
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Trigonometric identities
Examples 13:
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1.1 Trigonometric concepts
Examples 14: