Formulas of trigonometric functions is an important concept in mathematics, which describes the relationship between the angles and sides of a triangle. Therefore, as a math teacher, I have compiled several commonly used formulas of formulas of trigonometric functions for you:

Sine theorem: sinA/a = sinB/b = sinC/c

Cosine theorem: c? = a？ + b？ - 2ab cosC

Tangent theorem: tanA = a/b

Cotangent theorem: cotA = b/a

The formula for the sum of two angles:? sin(A+B) = sinAcosB + cosAsinB

Two-angle difference formula: sin(A-B) = sinAcosB-cosAsinB.

Double angle formula: sin2A = 2sinAcosA, cos2A = cos? Sin. a、tan2A = (2tanA)/( 1-tan？ answer

Half-angle formula: sin (a/2) = sqrt [(1-COSA)/2]

Double angle formula:? sin3A = 3sinA - 4sin？ a、cos3A = 4cos？ A - 3cosA

Triple angle formula: sin3A = 3sinA-4sin? a、cos3A = 4cos？ A - 3cosA

Universal formula: sin (ab) = SINA COSB COSA SINB COS (ab) = COSA COSB? Sina sinb tan(A B)=(tanA tanB)/( 1？ tanAtanB)