please can you tell me what is the problem??

Error using sym/subsindex (line 855)

Invalid indexing or function definition. Indexing must follow MATLAB indexing. Function arguments must be symbolic

variables, and function body must be sym expression.

Error in Untitled4 (line 224)

up = sum((p*l*R) + (N.*tanp*R) - (u.*l*tanp*R))+((FSo.*T*(R.*cosaw)));

[Walter Roberson]

Did you happen to create a variable named sum ?

[MANOJ KUMAR]

yes..i got it now.

thank you.