MATLAB: LaTex in an annotation

latex

I'm trying to insert a formula into an annotation on a graph, my code is
annotation('textbox','interpreter','latex','String',str,'FitBoxToText','on');
str={'(1) $$y= \frac{1}{(1+x)^2} = \sum_{k=1}^\inftyk(-x)^{k-1}$$',…
'(2) $$y= sin^2(x) = \sum_{k=1}^\infty(-1)^{k+1}\frac{2^{2k-1}x^{2k}}{(2k)!}$$'…
'(3) $$y=e^{-x^2} = \sum_{k=1}^\infty(-1)^k\frac{x^{2k}}{k!}$$'};
However, this doesn't seem to work, any help is greatly appreciated.

Best Answer

Your ‘str’ variable must come before your annotation call.
You are missing curly braces in the ‘\infty’ argument.
Change the order of the statements, add the curly braces, and it works: 
str={'(1) $$y= \frac{1}{(1+x)^2} = \sum_{k=1}^\infty{k(-x)}^{k-1}$$',...
    '(2) $$y= sin^2(x) = \sum_{k=1}^\infty{(-1)}^{k+1}\frac{2^{2k-1}x^{2k}}{(2k)!}$$'...
    '(3) $$y=e^{-x^2} = \sum_{k=1}^\infty{(-1)}^k\frac{x^{2k}}{k!}$$'};
annotation('textbox','interpreter','latex','String',str,'FitBoxToText','on');
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