The finite difference approximation of (d^{2} U / d x^{2}+alpha^{2} U=0) at (x_{i}) is given by a. (U_{i+1}-left(2-h^{2} alpha^{2} ight) U_{i}+U_{i-1}=0) b. (U_{i+1}-2 U_{i}+U_{i+1}=0) c.

The finite difference approximation of \(d^{2} U / d x^{2}+\alpha^{2} U=0\) at \(x_{i}\) is given by

a. \(U_{i+1}-\left(2-h^{2} \alpha^{2}\right) U_{i}+U_{i-1}=0\)

b. \(U_{i+1}-2 U_{i}+U_{i+1}=0\)

c. \(U_{i+1}-\left(2-\alpha^{2}\right) U_{i}+U_{i-1}=0\)