Q58 / 90 · JEE Main 2021 (27 Aug Shift 1) · Mathematics

If y1/4+y-1/4=2x, and x2-1d2ydx2+αxdy dx+βy=0, then |α-β| is equal to _______.

Correct answer: 17

Solution

y14+1y14=2x

y142-2xy14+1=0

y14=x+x2-1& x-x2-1

So, 141y34 dydx=1+xx2-1

141y34dydx=y14x2-1

dydx=4yx2-1   ...1

Hence 

d2ydx2=4x2-1y'-xyx2-1x2-1

x2-1y"=4x2-1y'-xyx2-1

x2-1y'=4x2-1y'-xyx2-1

x2-1y"=44y-xy'4  1

x2-1y"+xy'-16y=0

So  α-β=17

Hence, the correct answer is 17.

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