A) Calculations used exclusively for finding the area of a circle.
B) Formulas that only apply to angles in the first quadrant.
C) Equalities involving trigonometric functions that are true for every value of the occurring variables for which both sides are defined.
D) Equations that define the side lengths of a right triangle.

A) Triangle identities are only used in Euclidean space.
B) Trigonometric identities involve functions of angles, whereas triangle identities may involve side lengths or other lengths.
C) There is no difference; the terms are used interchangeably.
D) Trigonometric identities are always more complex than triangle identities.

A) Calculating the volume of non-Euclidean spheres.
B) The integration of non-trigonometric functions via substitution.
C) Simplifying algebraic polynomials without variables.
D) Determining the probability of geometric intersections.

A) sin² θ + cos² θ = 1
B) sin² θ + cos² θ = 0
C) sin θ + cos θ = 1
D) sin² θ - cos² θ = 1

A) x² + y² = 0
B) x² - y² = 1
C) x² + y² = 1
D) x + y = 1

A) 1 + tan² θ = sec² θ
B) 1 + cot² θ = csc² θ
C) sec² θ + csc² θ = 1
D) sin² θ + cos² θ = tan² θ

A) csc² θ + sec² θ = 1
B) sin² θ + cos² θ = cot² θ
C) 1 + cot² θ = csc² θ
D) 1 + tan² θ = sec² θ

A) θ' = 2θ - α
B) θ' = 2α - θ
C) θ' = α - θ
D) θ' = α + θ

A) π
B) π/2
C) 2π
D) 4π

A) tan θ
B) sec θ
C) cos θ
D) csc θ