# Table of the reduction Formulas for trigonometric functions: sine, cosine, tangent, and cotangent

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# Chapter 8. Trig Cheat Sheet (Useful Trigonometric Identities)

# Table of the reduction Formulas for trigonometric functions: sine, cosine, tangent, and cotangent

# Fundamental Trigonometric Identities

# The Pythagorean trigonometric identity

# Relations Between Tangent and Cotangent

# Relations Between Trigonometric Functions

# Trigonometric Formulas of Sums and Differences of Angles

# Sine and Cosine of the sum and difference of angles

# Tangent and Cotangent of the sum and difference of angles

# Secant and Cosecant of the sum and difference of angles

# Trigonometric Formulas of a double angle

# Formulas of the sine and cosine of a double angle

# Formulas of the tangent and cotangent of a double angle

# The trigonometric Formulas of a triple angle

# The sine of a triple angle

# The cosine of a triple angle

# The tangent of a triple angle

# The cotangent of a triple angle

# Half Angle Formulas. Trigonometric Power Reduction Formulas

# Sine of a half angle

# Cosine of a half angle

# Tangent of a half angle

# Cotangent of a half angle

# Expression of trigonometric functions through the tangent of a half argument

# Expression of sine through the tangent of a half angle

# Expression of cosine through the tangent of a half angle

# Expression of tangent through the tangent of a half angle

# Expression of cotangent through the tangent of a half angle

# Formulas of universal trigonometric substitution

# Sum to Product Formulas

# Formulas of the sum and difference of sines

# Formulas of the sum and difference of cosines

# Formulas of the sum and difference of tangents

# Product to Sum Formulas

# The product of sine and cosine:

# The product of cosines:

# The product of sines:

# The product of tangents:

# The product of cotangents:

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We can use the Pythagorean identity to solve for sin α or cos α:

We can use the Pythagorean identity to solve for tan α or cot α:

and:

In a right triangle, the sine of one acute angle equals the cosine of the other acute angle

or

Or

Or

** **

Or

Or

** **

Or

MATHVOX

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