The central difference approximation of (d^{2} x / d t^{2}) at (t_{i}) is given by a. (frac{1}{h^{2}}left(x_{i+1}-2 x_{i}+x_{i-1} ight)) b. (frac{1}{h^{2}}left(x_{i+1}-x_{i-1} ight)) c. (frac{1}{h^{2}}left(x_{i}-x_{i-1} ight))

The central difference approximation of \(d^{2} x / d t^{2}\) at \(t_{i}\) is given by

a. \(\frac{1}{h^{2}}\left(x_{i+1}-2 x_{i}+x_{i-1}\right)\)

b. \(\frac{1}{h^{2}}\left(x_{i+1}-x_{i-1}\right)\)

c. \(\frac{1}{h^{2}}\left(x_{i}-x_{i-1}\right)\)