2) ie . Q20

ist put x=0 u get y= ae^pi/2

take log on both sides

write it as 1/2 log(x^2+y^2)

now differentiate and simplify

ull get x+y dy/dx = x dy/dx - y

x+y= (x-y)dy/dx ..............1)

put x=0 dy/dx = -1

now differentiate eqn 1) again

1+dy/dx = (1-dy/dx)dy/dx + (x-y) d^2y/dx^2

put x=0,also whn x=0 dy/dx=-1 and y= a e^pi/2

put all the values ull get d^2/dx^2 = -2/a(e ^ -pi/2)

i hope its clear