F[x0 x0 x1 x1]

I got this to equal f'[x] + f'[x0] -2f[x0x1] / (x1-x0)

Which I think it's correct but I'm having trouble with this one

F[x0x0x0x1]

if i had to take a guess id think it was
f ' '(x0) - f[x1 x0]/2(x1-x0)

but im not sure anyone wana take a stab at it?

Never mind im dumb wrote it wrong on my paper