How to code a special equation?

Dynare help (legacy posts)
1

How can I code the equation below?
The equation is displayed in the picture.
http://hi.baidu.com/yidqxzjhwgjoqxe/item/e547364d0a37efb2833ae146
Thanks a lot for your attention and kindness!

2

There is no image here. Try attaching a pdf.