Hey Alan. Thanks for your words.Yes, I have asked and posted 3 related topics. They are similar but not totally the same. There are 2 topics that look the same (with the same equation). That is because I copy the Latex Equation from one to another one and would like to do some change. But then when one is changed, another one change automatically. I have tried to make it different, but not succeed.But the good news is that, now I have figured out all 3 topics, with the help of you and other online friends, especially foxkingdom. I learn a lot from him