|
|
|
|
|
|||||||||
|
|
|||||||||||||
|
|
UNIT 7 : TRIGONOMETRIC FUNCTIONS
LESSON 6
: TRIGONOMETRIC IDENTITIES
Definition: An Identity is a mathematical statement that is true for all values of the variable
in the given domain.
Example 1: x2
+ x = x(x + 1)
This
statement is an identity as it is true for all x in the real number system
Proof:
We prove this by showing that the Left side of the equation equals the
Right side.
L.S. = x2 + x R.S.
= x(x + 1)
= x2 + x
Therefore L.S. = R.S. and the identity is proven.
Basic Trigonometric Identities :
Example 2:
Proof:
Example 3:
Proof:
