Tuesday, 19 April 2016

Trignometric Identities

Trignometry is an important branch in mathematics that co relates sides of a triangle with angles of a triangle. Tri means 3 , gon means side and metry means measure . Trignometric iden
tities are simply equations that hold true for all given angles.

Prove the following trignometric identity :

(1 - Cos²A).Cosec²A = 1

solution

sin² + cos² = 1
=> sin² = 1 - cos²
=> LHS = sin²A . Cosec²A
 = sin²A . 1/sin²A  (since, sinA = 1/cosecA)
= 1
LHS = RHS
Hence Proved

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