11. Write all the Trigonometric Equations ?
Answers
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Basic Formulas
- sin θ = Opposite Side/Hypotenuse.
- Cos θ = Adjacent Side/Hypotenuse.
- tan θ = Opposite Side/Adjacent Side.
- sec θ = Hypotenuse/Adjacent Side.
- cosec θ = Hypotenuse/Opposite Side.
- cot θ = Adjacent Side/Opposite Side.
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Step-by-step explanation:
rigonometry ratios for a right-angled triangle can be written as;
sinθ = OppositesideHypotenuse
cosθ = AdjacentSideHypotenuse
tanθ = OppositesideAdjacentSide
secθ = HypotenuseAdjacentside
cosecθ = HypotenuseOppositeside
cotθ = AdjacentsideOppositeside
Trigonometric Ratios for Unit Circle
Similarly, for a unit circle, for which radius is equal to 1, and θ is the angle. The value of hypotenuse and adjacent side here is equal to the radius of the unit circle.
Hypotenuse = Adjacent side to θ = 1
Therefore, the ratios of trigonometry are given by:
sin θ = y/1 = y
cos θ = x/1 = x
tan θ = y/x
cot θ = x/y
sec θ = 1/x
cosec θ = 1/y
Trigonometry Identities
Tangent and Cotangent Identities
tanθ = sinθcosθ
cotθ = cosθsinθ
Reciprocal Identities
sinθ = 1/cosecθ
cosecθ = 1/sinθ
cosθ = 1/secθ
secθ = 1/cosθ
tanθ = 1/cotθ
cotθ = 1/tanθ
Pythagorean Identities
sin2θ + cos2θ = 1
1 + tan2θ = sec2θ
1 + cot2θ = cosec2θ
Even and Odd Angle Formulas
sin(-θ) = -sinθ
cos(-θ) = cosθ
tan(-θ) = -tanθ
cot(-θ) = -cotθ
sec(-θ) = secθ
cosec(-θ) = -cosecθ
Co-function Formulas
sin(900-θ) = cosθ
cos(900-θ) = sinθ
tan(900-θ) = cotθ
cot(900-θ) = tanθ
sec(900-θ) = cosecθ
cosec(900-θ) = secθ
Double Angle Formulas
sin2θ = 2 sinθ cosθ
cos2θ = 1 – 2sin2θ
tan2θ = 2tanθ1−tan2θ
Half Angle Formulas
sinθ = ±1−cos2θ2−−−−−−√
cosθ = ±1+cos2θ2−−−−−−√
tanθ = ±1−cos2θ1+cos2θ−−−−−−√
Thrice of Angle Formulas
sin3θ = 3sinθ – 4 sin3θ
Cos 3θ = 4cos3θ – 3 cosθ
Tan 3θ = 3tanθ–tan3θ1−3tan2θ
Cot 3θ = cot3θ–3cotθ3cot2θ−1
Sum and Difference Formulas
Sin (A+B) = Sin A Cos B + Cos A Sin B
Sin (A-B) = Sin A Cos B – Cos A Sin B
Cos (A+B) = Cos A Cos B – Sin A Sin B
Cos (A-B) = Cos A Cos B + Sin A Sin B
Tan (A+B) = TanA+TanB1–TanATanB
Tan (A-B) = TanA–TanB1+TanATanB
Product to Sum Formulas
Sin A Sin B = ½ [Cos (A-B) – Cos (A+B)]
Cos A Cos B = ½ [Cos (A-B) + Cos (A+B)]
Sin A Cos B = ½ [Sin (A+B) + Sin (A-B)]
Cos A Sin B = ½ [Sin (A+B) – Sin (A-B)]
Sum to Product Formulas
Sin A + Sin B = 2 sin A+B2 cos A−B2
Sin A – Sin B = 2 cosA+B2 sin A−B2
Cos A + Cos B = 2 cosA+B2 cos A−B2
Cos A – Cos B = – 2 sinA+B2 sin A−B2
Inverse Trigonometric Functions
If Sin θ = x, then θ = sin-1 x = arcsin(x)
Similarly,
θ = cos-1x = arccos(x)
θ = tan-1 x = arctan(x)
Also, the inverse properties could be defined as;
sin-1(sin θ) = θ
cos-1(cos θ) = θ
tan-1(tan θ) = θ
Unit Circle
With the help of unit circle, we can see here the different values of sin and cos ratios for different angles such as 0°, 30°, 45°, 60°, 90°, and so on in all the four quadrants.
Trigonometry Formulas List-Unit Circle
Trigonometry Table
Degrees 0° 30° 45° 60° 90° 180° 270° 360°
Radians 0 π/6 π/4 π/3 π/2 π 3π/2 2π
Sin θ 0 1/2 1/√2 √3/2 1 0 -1 0
Cos θ 1 √3/2 1/√2 1/2 0 -1 0 1
Tan θ 0 1/√3 1 √3 ∞ 0 ∞ 0
Cot θ ∞ √3 1 1/√3 0 ∞ 0 ∞
Sec θ 1 2/√3 √2 2 ∞ -1 ∞ 1
Cosec θ ∞ 2 √2 2/√3 1 ∞ -1 ∞
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