Everything Maths, Grade 10. Chapter 5: Trigonometry.

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5. Trigonometry
Grade 10

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Trigonometric ratios
● We can define three trigonometric ratios for right-angled triangles;
sine (sin), cosine (cos) and tangent (tan):

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Reciprocal functions
● Each of the three trigonometric functions has a reciprocal. The reciprocals,
cosecant (cosec), secant (sec) and cotangent (cot):

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Special angles
● The values of the trigonometric functions for these special angles are listed in the table:

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Trigonometric ratios in
the Cartesian plane
● We can write all the
trigonometric functions in
terms of x, y and r.
● We use the CAST diagram to
determine in which quadrants
the trigonometric ratios are
positive and negative.

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Special angles extended
We can extend our knowledge of special angles using the definitions of the trig ratios in the
Cartesian plane.

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