Trig Identities

Front

What is the Pythagorean identity for sine and cosine?

Back

sin²θ + cos²θ = 1

Front

What is the definition of cosecant (csc)?

Back

cscθ = 1/sinθ

Front

What is the definition of secant (sec)?

Back

secθ = 1/cosθ

Front

What is the definition of cotangent (cot)?

Back

cotθ = 1/tanθ = cosθ/sinθ

Front

What is the relationship between tangent and sine/cosine?

Back

tanθ = sinθ/cosθ

Front

What is the double angle formula for sine?

Back

sin(2θ) = 2sinθcosθ

Front

What is the double angle formula for cosine?

Back

cos(2θ) = cos²θ - sin²θ

Front

What is the sum of angles formula for sine?

Back

sin(a + b) = sin(a)cos(b) + cos(a)sin(b)

Front

What is the sum of angles formula for cosine?

Back

cos(a + b) = cos(a)cos(b) - sin(a)sin(b)

Front

Simplify: csc²θ - cot²θ

Back

1 (Pythagorean identity)