Dear all, why \vec{r} is invalid? The result is just a "r" with no vector symbol. In addition: miktex version is 2.8 With warm regards and thanks Caihong Zhang
View entire thread
You seem to have CSS turned off. Please don't fill out this field.
Click URL instructions: Right-click on the ad, choose "Copy Link", then paste here → (This may not be possible with some types of ads)
Ad destination/click URL: