Question

what are the formulaes of trigonometry ​

Answer 1

sin2A=2sinA.CosA
Cos2a=cos^2 - sin^2

Answer 2

HEY MATE HERE'S YOUR ANSWER ;



sinθ=OppositeHypotenuse

secθ=HypotenuseAdjacent

cosθ=AdjacentHypotenuse

tanθ=OppositeAdjacent

cosecθ=HypotenuseOpposite

cotθ=AdjacentOpposite

The Reciprocal Identities are given as:

cosecθ=1sinθ

secθ=1cosθ

cotθ=1tanθ

sinθ=1cosecθ

cosθ=1secθ

tanθ=1cotθ


sin(90∘−x)=cosxcos(90∘−x)=sinxtan(90∘−x)=cotxcot(90∘−x)=tanx

Trigonometry Formulas involving Sum/Difference Identities:

sin(x+y)=sin(x)cos(y)+cos(x)sin(y)cos(x+y)=cos(x)cos(y)–sin(x)sin(y)tan(x+y)=tanx+tany1−tanx⋅tanysin(x–y)=sin(x)cos(y)–cos(x)sin(y)cos(x–y)=cos(x)cos(y)+sin(x)sin(y)tan(x−y)=tanx–tany1+tanx⋅tany


Trigonometry Formulas involving Product identities:

sinx⋅cosy=sin(x+y)+sin(x−y)2cosx⋅cosy=cos(x+y)+cos(x−y)2sinx⋅siny=cos(x+y)−cos(x−y)2

Trigonometry Formulas involving Sum to Product Identities:

sinx+siny=2sinx+y2cosx−y2sinx−siny=2cosx+y2sinx−y2cosx+cosy=2cosx+y2cosx−y2cosx−cosy=−2sinx+y2sinx−y2

Trigonometry Formulas involving Double Angle Identities:

sin(2x)=2sin(x).cos(x)cos(2x)=cos2(x)–sin2(x)cos(2x)=2cos2(x)−1cos(2x)=1–2sin2(x)tan(2x)=[2tan(x)][1−tan2(x)]


Trigonometry Formulas involving Half Angle Identities:

sinx2=±1−cosx2−−−−−−√cosx2=±1+cosx2−−−−−−√tan(x2)=1−cos(x)1+cos(x)−−−−−−√

Also, tan(x2)=1−cos(x)1+cos(x)−−−−−−√=(1−cos(x))(1−cos(x))(1+cos(x))(1−cos(x))−−−−−−−−−−−−−√=(1−cos(x))21−cos2(x)−−−−−−−−√=(1−cos(x))2sin2(x)−−−−−−−−√=1−cos(x)sin(x) 

Trigonometry Formulas involving Cofunction Identities – degree:

sin(90∘−x)=cosxcos(90∘−x)=sinxtan(90∘−x)=cotxcot(90∘−x)=tanx