Expert: George Moustris - 7/6/2006

Question
I have to partially differentiate the following function w by use of symbolic math tool box.I have written the following  in the command window:But error comes as : Missing MATLAB operator.
I have to double partially differentiate w with respect to R and x .
Please suggest how to do it.

syms A0 A R t B A1 x;
w = A0*[R+A*(R^(t+1))+B*(R^3)] + A1*[(R^2)+A*(R^(t+2))+B*(R^4)]cosx;

Answer
Hi vinayakranjan ,

at first glance the problem seems to be with the cosx. It should be A0*[R+A*(R^(t+1))+B*(R^3)] + A1*[(R^2)+A*(R^(t+2))+B*(R^4)]*cos(x)
you have forgot the multiplication operator (*) and the cosine function is cos(x) not cosx.
Try this. If it doesn't work, drop me a note to look at it further.

Best
G.