Really cool heat transfer problem - rocket science

Hi I am just having a problem with my project , if you can please give me an advice. error is index exceeds matrix dimensions. Thank you

[Walter Roberson]

Duplicates http://www.mathworks.com/matlabcentral/answers/309698-i-am-getting-nan-as-answer-in-the-code-can-please-give-me-some-advice