NDA2018MathematicsTrigonometric Ratios & IdentitiesActual
If A= ^2 + ^4 , the for all real , which one of the following is correct?
Options
- A1 A 2
- B3 4 A 1
- C13 16 A 1
- D3 4 A 13 16
Correct answer
B. 3 4 A 1
Step-by-step solution
aligned A & = ^2 + ^4 & = ^2 + (1- ^2 )^2 & =1+ ^4 - ^2 & =1- ^2 (1- ^2 ) & =1- ^2 ^2 & = 4-4 ^2 ^2 4 = 4- ^2(2 ) 4 aligned As, we know, 0 ^2 2 1 A = 4-0 4 or 4-1 4 3 4 A 1