Chapter 3, "Trigonometry Snippets"

Degrees to Radians

Angle in degrees * = angle in radians.

Radians to Degrees

Angle in radians * = angle in degrees.

Trigonometric Functions

where opp = the side opposite a, adj = the side adjacent to a, and hyp = the hypotenuse.

Other Trigonometric Functions

where opp = the side opposite a, adj = the side adjacent to a, and hyp = the hypotenuse.

Period of the Sine Wave

For y = sin(Bx), the period = .

Amplitude of the Sine Wave

For y = Asin(x), the amplitude = |A|.

Unit Circle Identity

cos²a + sin²a = 1

Tangent and Cotangent

Negative Angles

sin(–a) = –sina

cos(–a) = cosa

tan(–a) = –tana

Sum and Difference Identities for Sine

sin(a₁ + a₂) = sina₁cosa₂ + cosa₁sina₂

sin(a₁ – a₂) = sina₁cosa₂ – cosa₁sina₂

Sum and Difference Identities for Cosine

cos(a₁ + a₂) = cosa₁cosa₂ – sina₁sina₂

cos(a₁ – a₂) = cosa₁cosa₂ + sina₁sina₂