I have a data set with unequally spaced points:x 11.11.3f (x)21.91.5I would like to estimate f (1) with a second order accurate method, but we dont havea formula for it!(a)(8 points) Derive a second order accurate finite difference method using x0, x0+ h,and x0+3h. Your formula will take the form:f (x0)= Af (x0)+ Bf (x0+ h)+ Cf (x0+3h)Dh + O(h2)The derivation will involve the 2nd degree Taylor polynomial evaluated at x0+ hand x0+3h. Follow the steps from class. Clearly show the error term O(h2) resultin your derivation