LaTex in an annotation

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.

Answer 1

[Star Strider]

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');