Try this:
str1={['$x(\infty)=',num2str(y(1,end),'%1.4f'),'$'], ['$1 -\frac{1}{\alpha(2)}=',num2str(yt,'%9.4f') '$']};
text(0.05,(1-0.05),str1, 'Interpreter','latex')
I am not certain what result you want. There may be easier and more efficient ways to create these strings, however this works.
EDIT —
Alternatively, if you want them on one line:
str1={['$x(\infty)=',num2str(y(1,end),'%1.4f'),'$, $1 -\frac{1}{\alpha(2)}=',num2str(yt,'%9.4f') '$']};
text(0.05,(1-0.05),str1, 'Interpreter','latex')
