anybody give ch 8 formulas class 10th Trigonometry
Answers
Answer:
Step-by-step explanation:
1. Sin (A+B) = SinA x CosB + CosA x SinB
2. Sin (A-B) = SinA x CosB – CosA x SinB
3. Cos (A+B) = CosA x CosB – SinA x SinB
4. Cos (A-B) = CosA x CosB + SinA x SinB
5. Tan (A+B) = (TanA + TanB)/(1 – TanA x TanB)
6. Tan (A-B) = (TanA – TanB)/(1 + TanA x TanB)
7. Sin2A = 2SinACosA
OR
= 2TanA/(1+Tan2A)
8. Cos2A = Cos2A – Sin2A
OR
= 1 – 2Sin2A
OR
= 2Cos2A – 1
OR
= (1-Tan2A)/(1+Tan2A)
9. Sin3A = 3SinA – 4Sin3A
10. Cos3A = 4Cos3A – 3CosA
11.Tan3A = (3TanA-4Tan2A)/(1+3Tan2A)
12. SinA x Sin2A X Sin4A = ¼ Sin3A
13. CosA x Cos2A x Cos4A = ¼ Cos3A
14. TanA x Tan2A x Tan4A = Tan3A
ANSWER:
1. sin A Perpendicular/Hypotenuse
2. cos A Base/Hypotenuse
3. tan A Perpendicular/Base
4. cot A Base/Perpendicular
5. cosec A Hypotenuse/Perpendicular
6. sec A Hypotenuse/Base
Trigonometric Sign Functions
sin (-θ) = − sin θ
cos (−θ) = cos θ
tan (−θ) = − tan θ
cosec (−θ) = − cosec θ
sec (−θ) = sec θ
cot (−θ) = − cot θ
Trigonometric Identities
sin2A + cos2A = 1
tan2A + 1 = sec2A
cot2A + 1 = cosec2A
Periodic Identities
sin(2nπ + θ ) = sin θ
cos(2nπ + θ ) = cos θ
tan(2nπ + θ ) = tan θ
cot(2nπ + θ ) = cot θ
sec(2nπ + θ ) = sec θ
cosec(2nπ + θ ) = cosec θ
Complementary Ratios
Quadrant I
sin(π/2−θ) = cos θ
cos(π/2−θ) = sin θ
tan(π/2−θ) = cot θ
cot(π/2−θ) = tan θ
sec(π/2−θ) = cosec θ
cosec(π/2−θ) = sec θ
Quadrant II
sin(π−θ) = sin θ
cos(π−θ) = -cos θ
tan(π−θ) = -tan θ
cot(π−θ) = – cot θ
sec(π−θ) = -sec θ
cosec(π−θ) = cosec θ
Quadrant III
sin(π+ θ) = – sin θ
cos(π+ θ) = – cos θ
tan(π+ θ) = tan θ
cot(π+ θ) = cot θ
sec(π+ θ) = -sec θ
cosec(π+ θ) = -cosec θ
Quadrant IV
sin(2π− θ) = – sin θ
cos(2π− θ) = cos θ
tan(2π− θ) = – tan θ
cot(2π− θ) = – cot θ
sec(2π− θ) = sec θ
cosec(2π− θ) = -cosec θ
Sum and Difference of Two Angles
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) = [(tan A + tan B)/(1 – tan A tan B)]
tan(A-B) = [(tan A – tan B)/(1 + tan A tan B)]
Double Angle Formulas
sin2A = 2sinA cosA = [2tan A + (1+tan2A)]
cos2A = cos2A–sin2A = 1–2sin2A = 2cos2A–1= [(1-tan2A)/(1+tan2A)]
tan 2A = (2 tan A)/(1-tan2A)
Thrice of Angle Formulas
sin3A = 3sinA – 4sin3A
cos3A = 4cos3A – 3cosA
tan3A = [3tanA–tan3A]/[1−3tan2A]