BASIC TRIGONOMETRY

What is Trigonometry?

• Trigonometry is a branch of mathematics that studies relationships between the sides and angles of triangles.

Hypotenuse, Opposite and Adjacent

• Hypotenuse 
• the side opposite the right angle
• the longest side in a right triangle

• Opposite 
• across from a given angle

• Adjacent 
• The non-hypotenuse side that is next to the given angle

Trigonometric Ratios in Right Triangles

• The ratios of the sides of a right triangle are called trigonometric ratios.
• Three common trigonometric ratios are the sine (sin), cosine (cos), and tangent (tan). These are defined for acute angle A below:

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• The terms opposite, adjacent, and hypotenuse refer to the lengths of the sides.

SOH-CAH-TOA

• The word SOH-CAH-TOA helps us remember the definitions of sine, cosine, and tangent.

Complementary Angles

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(Proved!)

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Reciprocal Trigonometric Ratios

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The cosecant (csc):

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The secant (sec):

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The cotangent (cot):

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Basic Angles

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Negative Angles

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Complementary Angles

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Special Angles

Test yourself !