some functions aren't rendering

[ALEXeddy19]

i have been trying to write mathematical expression in normal font style rather than the san-serif font style by writting \ infront of the expression for example $\Ans$ but its still showing in san- serif font style and also the over head bar \ov isn't working,for example $\ov X$ gives me ov X which is not suppose to be so , am working on a android app calculator and am running it on android 13 and android 10