Finite difference approximation question

[volcano90]

Hi,

I have a question regarding finite difference approximation:
Consider the finite difference approximation
u'(xj-1/2) + λu(xj−1/2) ≈ 1/h*[u(xj ) − u(xj−1)] + λ(θu(xj ) + (1 − θ)u(xj−1))

how can I Find the order of approximation as a function of θ?

I am really new in this field, so appreciate any kind answer.

Best

 

[volcano90]

nobody knows the answer ?