cos(A±B)=cosAcosB∓sinAsinB tan(A±B)=1∓tanAtanBtanA±tanB 倍角公式 sin2θ=2sinθcosθ cos2θ=cos2θ−sin2θ=2cos2θ−1=1−2sin2θ tan2θ=1−tan2θ2tanθ 半角公式 sin2θcos2θtan2θ=±21−cosθ=±21+cosθ=±1+cosθ1−cosθ=1+cosθsinθ 降幂公式 ...
Fundamental Trigonometric Identities (基本三角恒等式) Reciprocal Identities (倒数恒等式): sinθ=1/cscθ cosθ=1/secθ tanθ=1/cotθ cscθ=1/sinθ secθ=1/cosθ cotθ=1/tanθ Quotient Identities (商恒等式): tanθ=sinθ/cosθ cotθ=cosθ/sinθ Pythagorean Identities (毕达哥拉斯恒等式)...
Pythagorean Trigonometric identities are some of the fundamental Trigonometric identities that have been derived using thePythagoras theorem. These identities are – sin2θ + cos2θ = 1 or cos2θ = 1 – sin2θ or sin2θ = 1 – cos2θ sec2θ = 1 + tan2θ or sec2θ – tan2θ = 1...
Reciprocal identities sin θ = 1 csc θ csc θ = 1 sin θ cos θ = 1 sec θ sec θ = 1 cos θ tan θ = 1 cot θ cot θ = 1 tan θProofAgain, in calculation we may replace either member of the identity with the other. And so if we see "sin θ", then we may, if we...
Trigonometric Identities Summary tanθ=sinθcosθ\displaystyle \tan{\theta}=\frac{{ \sin{\theta}}}{{ \cos{\theta}}}tanθ=cosθsinθ sin2θ+cos2θ=1\displaystyle{{\sin}^{2}\theta}+{{\cos}^{2}\theta}={1}sin2θ+cos2θ=1 ...
Co-Function Identities: Co-function identities relate the trigonometric functions of complementary angles. Complementary angles are two angles that add up to 90 degrees (or π/2 radians). For example, sin(π/2 –θ) is equal to cos(θ), and cos(π/2 –θ) is equal to sin(θ). These...
Section2.1-BasicTrigonometricIdentities sin2cos21 1cos sin 1seccos 1cscsin sintancos coscotsin 1cottan sin2cos21 sin2cos2122tan1sec222coscoscos...
sin(−θ) = −sin(θ) cos(−θ) = cos(θ) tan(−θ) = −tan(θ)Double Angle IdentitiesHalf Angle IdentitiesNote that "±" means it may be either one, depending on the value of θ/2Angle Sum and Difference Identities
identities. FundamentalIdentitiesInChapter5weusedthedefinitionsofthe trigonometricfunctionstoderivethereciprocal,quotient,andPythagorean identities.Togetherwiththenegative-angleidentities,thesearecalledthe fundamentalidentities. FundamentalIdentities ReciprocalIdentities QuotientIdentities (continued) tan sin cos cot ...
The Trigonometric Identities we introduced the(Sines, Cosines and Tangents). We begin by reminding ourselves of the 2X + Cos2X = 1 In addition, there are relations called: Sin 2X = 2 Sin X Cos X Cos 2X = Cos2X - Sin2X Because SinX + CosX = 1, this last relation can also be ...