Aspirants who want to be the part of Indian Military Academy, Officers Training Academy, Indian Naval Academy and Indian Air Force Academy have to apply for **Combined Defence Services Examination**. CDS Exam is conducted by UPSC (Union Public Service Commission) twice every year which is a brilliant opportunity for all defence aspirants to join the armed forces serve their country.

**CDS Exam Educational eligibility:**

- IMA : The aspirants should possess graduation degree in any discipline from a recognized university or institute.
- OTA: The aspirants should possess graduation degree in any discipline from a recognized university or institute.
- For INA: The aspirants must have a degree in Engineering.
- For Air Force Academy: The aspirants should have passed 12th standard with Physics and Mathematics and having a degree from a recognized university or bachelor’s degree in engineering / technology.

**What are the eligibility criterions for CDS exam?**

**CDS Exam Online Coaching**

### Best Tips for UPSC CDS 2 2016 Written Exam Preparation

- Delaying will delay your rank: CDSE is not an exam where you can study up overnight and give the exam the next day, to score fairly good marks. The syllabus for CDSE is vast, and that is why you need time to prepare for the same. SO do not procrastinate and delay to start your preparations, if there is any time right to start the preparations it’s now.
- Know the syllabus first, candidates who are very good in general mathematics, English and GK, especially the freshers, never look and study the syllabus of CDS exam. Always study the syllabus of cds exam which will help you to understand what they might ask in cds exam paper. After you scan the whole cds exam syllabus, make sure you are filtering out topics where you do not need any preparation and you are 100% confident of clearing it, topics which you are not 100% confident are the one you want to prepare to clear CDS exam. Weed out the topics which you have zero knowledge on and keep them for last. So here the basic idea is to prepare as many as topics you can with 100% confident, even if you missed out 10% of the topics from Maths, English and GK it won’t affect you that much. To have better understanding of these topics, refer to the cds exam questions blueprint.
- Score via English: English questions are pretty much easy and straight, so they give a good chance of scoring in CDSE. There are books which will definitely help you in improving and preparing for English, one of them is Pearson’s.
- Current affairs bag direct marks: Yes, in the general awareness paper, very few questions are there which are direct, otherwise others will be based on either assertion, reasoning or paragraphs will be given from which questions will be asked. The direct questions are majorly from the current affairs portion.
- Refer to previous question papers of cds exam; this method of preparation is followed by many successful candidates since many years. So always solve 10-15 previous question papers and find out where you are lacking, focus on topics which you are sure about and you will succeed without any doubt. Check out for cds exam coaching online by ssbcrackexams for solved previous question papers.
- Consider various preparation sources like books, e-books, online preparation, online groupds, blogs etc. This will make your preparation rock solid and you will also discover things which you are not aware of while preparing with the single source. So extend your horizon to discover more things related to cds exam preparation, you never know what advantage you will get by preparing with all other sources.
- In SSBCrackExams we have launched our cds exam online coaching course by analyzing the need of present cds exam aspirant. We not only stick to the strict topic wise plan but also provide the tracker to analyzie the learning curve of the candidates, we assume there is less improvement when there is not feedback, our onlince course has high end reporting system which helps you to understand you weak and stronger sections of cds exam topics, this will not only help you to improve on those topics, but also save lot of time to focus on other things, may be another exam you are preparing for. You can check out more details on cds exam coaching on line.
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**List of Important formulas for CDS 2 2016 Exam**

**Geometry:**

- Equal chords of circle subtends equal angle at center and vice versa. If AB =CD in figure then
- Perpendicular from the center of the circle to a chord bisects the chord. If
- Equal chords of the circle are equidistant from Center. If AB=BD then GE=EF
- The angle subtended by an arc at the center is double the angle subtended by it at any point on the remaining part of the circle. In each case
- The sum of the either pair of opposite angles of cyclic quadrilateral is 180.a quadrilateral is cyclic if all the four vertices of it lie on a circle. Here
- The tangent at any point of a circle is perpendicular to the radius through the point of contact.
- The lengths of the tangents drawn from external point on circle are equal. Here PA=PB

**Speed Distance and Time**

- Speed = Distance/Time, Time = Distance/Speed, Distance = Speed * Time
- Km/hr to m/sec conversion: x Km/hr = [x * (5/18)] m/sec
- m/sec to Km/hr conversion: x m/sec = [x*(18/5)] Km/hr
- Suppose a man covers a certain distance at x Km/hr and equal at y Km/hr then, the average speed during the whole journey is [2xy/(x+y)] Km/hr

**CDSE Train Problems Tips**

- Time taken by a train of length l metres to pass a pole or standing man or a signal post is equal to the time taken by the train to cover l metres.
- Time taken by a train of length l metres to pass a stationery object of length b metres is the time taken by the train to cover (l + b) metres.
- Suppose two trains or two objects bodies are moving in the same direction at u m/s and v m/s, where u > v, then their relative speed is = (u – v) m/s.
- Suppose two trains or two objects bodies are moving in opposite directions at u m/s and v m/s, then their relative speed is = (u + v) m/s.
- If two trains of length a metres and b metres are moving in opposite directions at u m/s and v m/s, then, the time taken by the trains to cross each other = (a+b)/(u + v) sec.
- If two trains of length a metres and b metres are moving in the same direction at u m/s and v m/s, then, the time taken by the faster train to cross the slower train = (a + b)/(u – v) sec.

**CDSE Boat and Stream Formula**

- Downstream/Upstream: In water, the direction along the stream is called downstream. And, the direction against the stream is called upstream.
- If the speed of a boat in still water is u km/hr and the speed of the stream is v km/hr, then: Speed downstream = (u + v) km/hr. Speed upstream = (u – v) km/hr.
- If the speed downstream is a km/hr and the speed upstream is b km/hr, then: Speed in still water = ½ (a + b) km/hr; Rate of stream = ½ (a – b) km/hr.

**Algebra**

- (a + b)(a – b) = (a
^{2}– b^{2}) - (a + b)
^{2}= (a^{2}+ b^{2}+ 2ab) - (a – b)
^{2}= (a^{2}+ b^{2}– 2ab) - (a + b + c)
^{2}= a^{2}+ b^{2}+ c^{2}+ 2(ab + bc + ca) - (a
^{3}+ b^{3}) = (a + b)(a^{2}– ab + b^{2}) - (a
^{3}– b^{3}) = (a – b)(a^{2}+ ab + b^{2}) - (a
^{3}+ b^{3}+ c^{3}– 3abc) = (a + b + c)(a^{2}+ b^{2}+ c^{2}– ab – bc – ac)

Plzzz give more information about general studies