(Angles are given in degrees, 90 degrees, 180 degrees etc.)

I.

Sin(-θ)=-Sinθ

Cos(-θ) = Cosθ

tan(-θ) = -tanθ

cot(-θ) = -cotθ

sec(-θ) = secθ

cosec(-θ)= - cosecθII.

sin(90-θ) = cosθ

cos(90-θ) = sinθ

tan(90-θ) = cotθ

cot(90-θ) = tanθ

sec(90-θ) = cosecθ

cosec(90-θ) = secθIII.

sin(90+θ) = cosθ

cos(90+θ) = -sinθ

tan(90+θ) = -cotθ

cot(90+θ) = -tanθ

sec(90+θ) = -cosecθ

cosec(90+θ) = secθIV.

sin(180-θ) = sinθ

cos(180-θ) = -cosθ

tan(180-θ) = -tanθ

cot(180-θ) = cotθ

sec(180-θ) = -secθ

cosec(180-θ) = cosecθV.

sin(180+θ) = -sinθ

cos(180+θ) = -cosθ

tan(180+θ) = tanθ

cot(180+θ) = cotθ

sec(180+θ) = -secθ

cosec(180+θ) = -cosecθ

cot(180-θ)=-cotθ

since cot(180-θ)=1/tan(180-θ)

and CAT doesn't require the highest level of Geometry skills or Number theory skills. Beig familiar with UG level mathematics and to some extent PG level would do.

Hmm, its obvious because Cat opens the door for IIMs (best institute for management) just as IIT-JEE (or Jee advanced) opens the way for iits. There the problems are much tougher.

]]>The post has been rectified.

*Cos(A - B) - Cos(A + B) = 2SinASinB*

Please edit post #2, this is probably a typo Cos(A-B) - Cos(A-B) = 2SinASinB

Error spotted by Thuhina.

]]>At the request of a member I have cleaned this thread to only reflect proven formulas. Some errors as pointed out by John E. Franklin have now been checked and corrected.

]]>tan(2u)=2/(cot(u)-tan(u))

]]>I am sorry for the delay in replying,

Yes, I know about CAT, the general questioning pattern etc.

But what exactly do you want to know in Geometry and Number stuff?

Any prearatory CAT book gives the basics. And CAT doesn't require the highest level of Geometry skills or Number theory skills. Beig familiar with UG level mathematics and to some extent PG level would do.

The wikipedia always has much interesting stuff in geometric and number system, provided you know what exactly are the search words you use, and depending on your luck when choosing the relevance percentage.

There are some other interesting forums, sites on the net. If I were you, I would exhaust all search engines, and just hope I am lucky!

Not many engineers pursue the CAT, and most of them who do are likely to be successful. My cousin is one, just about my age, and he's now with an MNC at middle/top management.

My good wishes to you for the CAT, its November already.

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Formulas which express the sum or difference in product

Hey ganesh

i just joined this forum. i am an engineer. Am preparing for CAT exam.

am sure u knw abt CAT. (its this november) . So i was looking for some really interesting geometry and number system stuff

like some patterns or some formulaes

etc

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**Relation between circular and hyperbolic functions**

**Addition formulas for Hyperbolic functions**

**Periods of hyperbolic functions**

**Inverse Hyperbolic functions**

**Sine Formula (or Law of Sines)**

In any ΔABC,

**Cosine Formula (or Law of Cosines)**

In any ΔABC,

These formulas are also written as

**Projection formulas**

In any ΔABC,

**Half-Angles and Sides**

In any ΔABC,

**Area of a Triangle**

Hero's fromula

**Incircle and Circumcircle**

A circle which touches the three sides of a traingle internally is called the incircle.The center of the circle is called the incentre and the raidus is called the inradius.

If r is the inradius, then

The circle which passes through the vertices of a triangle is called the circumcircle of a triangle or circumscribing circle. The centre of this circle is the circumcentre and the radius of the circumcircle is the circumradius.

If R is the circumradius, then

If Δ is the area of the triangle,

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