content_image/326515.jpg content_image/326523.jpg content_image/326517.jpg content_image/326518.jpg content_image/326516.jpg
Therefore, we obtain 

<img src='content_image/326515.jpg'>

From (10), it follows that 

Substituting z = z$_{i}$ in (11), we obtain 

Therefore, we have 

Now we will find the order of Method 1. If the Taylor’s expansion is applied to P $^{′}$( z$_{i}$ − W$_{i}$ ), then we have 

<img src='content_image/326523.jpg'>

<img src='content_image/326517.jpg'>

<img src='content_image/326518.jpg'>

<img src='content_image/326516.jpg'>

