COMEDK2024Morning ShiftMathematicsTrigonometric Ratios & IdentitiesActual
If = 1 2 (x+ 1 x ) then 1 2 (x^2+ 1 x^2 )=
Options
- A^2 - ^2
- B2 ( ^2 - ^2 )
- C^2 - ^2
- D1 2 ( ^2 - ^2 )
Correct answer
A. ^2 - ^2
Step-by-step solution
Given = 1 2 (x + 1 x ) , we have x + 1 x = 2 . Squaring both sides: (x + 1 x )^2 = (2 )^2 x^2 + 1 x^2 + 2 = 4 ^2 x^2 + 1 x^2 = 4 ^2 - 2 Now, we need to find 1 2 (x^2 + 1 x^2 ) : 1 2 (x^2 + 1 x^2 ) = 1 2 (4 ^2 - 2) = 2 ^2 - 1 . Using the identity ^2 + ^2 = 1 , we can write 1 = ^2 + ^2 . Substituting this into the expression: 2 ^2 - ( ^2 + ^2 ) = ^2 - ^2 . Answer: ^2 - ^2