(Memo) Triangle Formula

Halfwidth formula:

(Positive and negative are determined by the quadrant) Triangle Formula:

	Acute angle trigonometric function	Any angle trigonometric function
Graphics	Right Triangle	Any angle trigonometric function
Sin)
Cosine (COS)
Tangent (tan or TG)
Cotangent (cot or CTG)
Cut (SEC)
Union cut (CSC)

Reciprocal Relationship:;. quotient relationship:;. Square relationship :;;. The following are special values: 

Sin30 ° = 1/2	Sin37 ° = 0.6	Sin45 ° = √ 2/2	Sin60 ° = √ 3/2	Sin15 ° = (√ 6-√ 2)/4	Sin75 ° = (√ 6 + √ 2)/4
Cos30 ° = √ 3/2	Cos37 ° = 0.8	Cos45 ° = √ 2/2	Cos60 ° = 1/2	Cos15 ° = (√ 6 + √ 2)/4	Cos75° = √ 6-√ 2)/4
Tan30 ° = √ 3/3	Tan37 ° = 3/4	Tan45 ° = 1	Tan60 ° = √ 3 [2]	Tan15 ° = 2-√ 3	Tan75 ° = 2 + √ 3
Cot30 ° = √ 3	Cot37 ° = 4/3	Cot45 ° = 1	Cot60 ° = √ 3/3
Sin18 ° = (√ 5-1)/4		This value is useful in high school competitions and self-recruitment, that is, half of the Golden cut.

  Induction formula: Formula 1:Set αIs any angle, and the same trigonometric function value of the angle with the same end edge is equal: Formula 2:Set αIs any angle, π+ αThe trigonometric value and αThe relationship between trigonometric values: Formula 3:Any angle- αAnd αThe relationship between trigonometric values: Formula 4: π- αAnd αThe relationship between trigonometric values: Formula 5:2 π- αAnd αThe relationship between trigonometric values: Formula 6: π/2 ± αAnd 3 π/2 ± αAnd αThe relationship between trigonometric values:

Sin (π/2 + α) = cos α	Cos (π/2 + α) =-sin α	Tan (π/2 + α) =-cot α	Cot (π/2 + α) =-tan α
Sin (π/2-α) = cos α	Cos (π/2-α) = sin α	Tan (π/2-α) = cot α	Cot (π/2-α) = tan α
Sin (3 π/2 + α) =-Cos α	Cos (3 π/2 + α) = sin α	Cot (3 π/2 + α) =-tan α	Tan (3 π/2 + α) =-cot α
Cot (3 π/2 + α) =-tan α	Sin (3 π/2-α) =-Cos α	Cos (3 π/2-α) =-sin α	Tan (3 π/2-α) = cot α
Cot (3 π/2-α) = tan α, generally not used	Note: The odd variation remains unchanged, and the symbol is in the quadrant. [3]

Basic formula of triangle: formula of difference angle and formula of difference product: adding a positive, while adding a surplus, adding a positive minus a margin, formula for negative sine product and difference times 2xUniversal Formula