NDA2025MathematicsDifferentiationActual
Consider the following for the two (02) items that follow: Let x = - and y = ^4 - ^4 . What is ( x^2+4 y^2+4 ) dy dx [(x^2+4) d^2y dx^2 - 16y ] equal to?
Options
- A16x
- B16y
- C-16x
- D-16y
Correct answer
C. -16x
Step-by-step solution
Given x = - and y = ^4 - ^4 . First, we simplify x^2 + 4 and y^2 + 4 : x^2 + 4 = ( - )^2 + 4 = ^2 + ^2 - 2 + 4 = ( + )^2 y^2 + 4 = ( ^4 - ^4 )^2 + 4 = ^8 + ^8 - 2 + 4 = ( ^4 + ^4 )^2 Differentiating x and y with respect to : dx d = + = ( + ) dy d = 4 ^3 ( ) - 4 ^3 (- ) = 4 ( ^4 + ^4 ) Now, finding dy dx : dy dx = dy d dx d = 4 ( ^4 + ^4 ) ( + ) = 4( ^4 + ^4 ) + Squaring both sides: ( dy dx )^2 = 16( ^4 + ^4 )^2 ( + )^2 = 16(y^2+4) x^2+4 Rearranging the equation: (x^2+4) ( dy dx )^2 = 16(y^2+4) Differentiating both