# Tips to Solve Trigonometry Questions in CDS 2016

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2572 Tips to Solve Trigonometry Questions in CDS 2016: The Union Public Services Commission (UPSC) will conduct the CDS (II) written examination on 23rd of October. Every year huge number of candidates apply for CDS exam to join Indian Military Academy, Officers Training Academy, Indian Naval Academy and Indian Air Force Academy.

UPSC CDS (II) exam for recruitment in Indian Armed forces, consists of three papers i.e. English, Elementary Mathematics and General Knowledge. Each of the paper carries equal weightage of marks i.e. 100 marks. Hence, it is important to give equal attention to each paper.

In this article, we will be focusing on one of the most important topics of elementary mathematics viz. Trigonometry. We will give you handy preparation tips to solve trigonometry questions in UPSC CDS exam. But first, lets have a look at the CDS (I) exam analysis of the trigonometry questions.

## Analysis of Number System questions in CDS (I) 2016 paper

The UPSC CDS (I) exam was conducted on 14th February. Here, we have mentioned a table which highlights the questions pattern for the trigonometry topic of CDS exam.

 Topic No. of questions Trigonometric Ratios 6 Sum, Difference & Product of trigonometric ratios 4 Height and Distance 2

From the above information, we can deduce that most of the questions were asked from trigonometric ratios. Thus, the importance of the particular topic gets further emphasized. However, one should not expect to get the same pattern in CDS (II) as well. It is important for candidates to prepare for each of the topics mentioned in the syllabus for UPSC CDS (II) Elementary Mathematics.

## Tips to Solve Trigonometry Questions in CDS

Weightage of trigonometry in CDS exam is around 12-15%, according to previous year’s papers. For CDS paper, you should focus more on identity type of questions rather than direct formula based questions. Trigonometric ratios are an integral part of this section and you should always give it first priority. To help you in your preparation we have mentioned some important tips to solve trigonometry questions in CDS exam. Have a look at these:

1. Familiarize yourself with the Pythagoras theorem and the concept of perpendicular, base and hypotenuse because perpendicular is always opposite to the angle “theta”.
2. Learn the conversion of trigonometric ratios into one from another ratio so that you can calculate the value of any other trigonometric ratio. You can easily learn the order by memorizing the mantra “Pandit Badri Prasad Har Har Bhole” (PBPHHB)

Sin      Cos   Tan

P          B       P

H         H       B

Cosec Sec   Cot

1. Memorize the value of ratios (0o, 15o, 30o, 45o, 60o, 90o) of Cosine, Sine and Tangent.
2. Even though trigonometric ratios have more importance, you should know the trigonometric identities as well.
3. Practice by using the perpendicular side as the opposite side of angle theta.
4. While solving the mathematical problems consider the symbols of trigonometric ratios carefully.
5. Always read the questions carefully during the exam. Mark the questions which you find difficult and try to solve them later.
6. In height and distance questions, keep in mind the form of angle (angle of elevation or angle of depression) given in the particular question.
7. Practice Language based questions that will help you in Height and Distance problems.
8. Your main focus should be on the identities and relations of tanθ, Cotθ, Secθ and Cosecθ.
9. Practice level-III questions so that you can solve level-I and level-II easily in the examination.

Apart from the given tips, it is important for you to learn some of the trigonometric identities and ratios which is given below:

sin2 θ + cos2 θ = 1

tan2 θ + 1 = sec2 θ

cot2 θ + 1 = cosec2 θ

Negative of a Function:

sin (–x) = –sin x

cos (–x) = cos x

tan (–x) = –tan x

cosec (–x) = –cosec x

sec (–x) = sec x

cot (–x) = –cot x

sin(x+y) = sinx cosy + cosx siny

sin(x-y) = sinx cosy – cosx siny

cos(x+y) = cosx cosy – sinx siny

cos(x-y) = cosx cosy + sinx siny

We hope all these preparation tips to solve trigonometry questions will prove beneficial for the upcoming UPSC CDS (II) Examination. If there any doubts or queries, let us know in the comments section below.