Question

Plz send me the trigonometry important formulas (10 th class).​

Answer 1

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]