find the second derivative
f(x)= 1/(4u^2-3)^2
f(u) = (4u^2-3)^-2
f' = -2(4u^2-3)(8u)
= -16u(4u^2-3)^-3
f" = -16(4u^2-3)^-2 + 48u(8u)(4u^2-3)^-4
= 16(20u^2+3)(4u^2-3)^-4
f(x)= 1/(4u^2-3)^2
f' = -2(4u^2-3)(8u)
= -16u(4u^2-3)^-3
f" = -16(4u^2-3)^-2 + 48u(8u)(4u^2-3)^-4
= 16(20u^2+3)(4u^2-3)^-4