Trigonometry topic is a part and parcel of Advanced Maths. If you are preparing for Bank exams or SSC exams or any aptitude exam, you have to learn few rules and formulas to solve the questions in exams in minimum possible time.

Direct formula can greatly help you in the exams where you have to attempt 200 questions in 120 minutes. It is also important in Mains exam of SSC and IBPS examination. So, i am going to specify the few set of rules which can help you in your question solving strategy.

#### Basic Concept of Trigonometry:

– It is a branch of mathematics that deals with lengths and angles of triangles (according to Wikipedia).

Let, ABC be a right angled triangle with angle C = 90. The Perpendicular (P) be the height BC (opposite to the angle θ ) and the Base (B) be the length AC, and the Hypotenuse (H) be the distance AB between AC and BC.

Image:Wikipedia.org
• Sinθ = P/H = 1/cosecθ
• Cosθ = B/H = 1/Secθ
• Tanθ = P/B = Sinθ/Cosθ

• Sin2θ + Cos2θ = 1
• Cosec2θ = 1 + Cot2θ
• Sec2θ = 1 + Tan2θ

#### Trigonometry Ratios of Specified Angles:

1.  Sin(A+B) = SinA.CosB + CosA.SinB
2. Sin(A-B) = SinA.CosB – CosA.SinB
3. Cos(A+B) = CosA.CosB – SinA.SinB
4. Cos(A-B) = CosA.CosB + SinA.SinB
5. 2 SinA.CosB = Sin (A+B) + Sin (A-B)
6. 2 CosA.SinB = Sin (A+B) – Sin (A-B)
7. 2 SinA.SinB = Cos (A+B) – Cos (A-B)
8. 2 CosA.CosB = Cos (A+B) + Cos (A-B)
9. Sin A + Sin B = 2 Sin (A+B)/2.Cos (A-B)/2
10. Sin A – Sin B = 2 Sin (A-B)/2.Cos (A+B)/2
11. Cos A + Cos B = 2 Cos (A+B)/2.Cos(A-B)/2
12. Cos A – Cos B = 2 Sin (A+B)/2.Sin (A-B)/2
13. Sin2A – Sin2B = Sin(A+B) – Sin(A-B)
14. Cos2A- Cos2B = Cos(A+B) – Cos(A-B)