Step-by-step explanation:
To prove :
( 1 - sin x ) ( 1 + sin x ) = sec² x
LHS : -
( 1 - sin x ) ( 1 + sin x )
Formula / Identity : -
( a - b ) ( a + b ) = a² - b²
Here,
a = 1
b = sin x
( 1 - sin x ) ( 1 + sin x )
= 1 - sin² x
Identify : -
sin² θ + cos² θ = 1
cos² θ = 1 - sin² θ
Similarly,
1 - sin² x
= cos² x
= RHS
Hence verified.
The answer is going to be A!!!
You could say 84/2, 126/3, or even 168/4
