How to solve '' error(mess​age('symbo​lic:sym:er​rmsg1')); ''

syms m x y z n k xx. yy. zz.

n = 1.6;

k = 0.000005;

x = linspace(-0.000015, 0.000015, 10);

z = linspace(-0.00003, 0.00003, 10);

[xx, zz] = meshgrid(x, z);

yy = symsum(1i^(-m)*exp(1i*m*atan(zz./xx)).*(besselj(m,k*sqrt(xx.^2+zz.^2))-((n*diff(besselj(m,n*k*10^(-6)))*besselj(m,k*10^(-6))-besselj(m,n*k*10^(-6))*diff(besselj(m,k*10^(-6))))/(n*diff(besselj(m,n*k*10^(-6)))*besselh(m,k*10^(-6))-besselj(m,n*k*10^(-6))*diff(besselh(m,k*10^(-6)))))*besselh(m,k.*sqrt(xx.^2+zz.^2))),m,0,10);

mesh(xx, yy, zz);

however, the system says:

>> Untitled2

Error using syms (line 265) error(message('symbolic:sym:errmsg1'));

Invalid variable name.

Error in Untitled2 (line 1)

syms m x y z n k xx. yy. zz.

Answer 1

[Fangjun Jiang]

remove the "." in "syms xx."

[I CHUN LIN]

Thank you.

I had done. But the result :

>> Untitled2

Error using symengine

Invalid variable.

Error in sym/symsum (line 70)

rSym = mupadmex('symobj::map',fsym.s,'symobj::symsum',x.s,a.s,b.s);

Error in Untitled2 (line 7)

yy =

symsum(1i^(-m)*exp(1i*m*atan(zz./xx)).*(besselj(m,k*sqrt(xx.^2+zz.^2))-((n*diff(besselj(m,n*k*10^(-6)))*besselj(m,k*10^(-6))-besselj(m,n*k*10^(-6))*diff(besselj(m,k*10^(-6))))/(n*diff(besselj(m,n*k*10^(-6)))*besselh(m,k*10^(-6))-besselj(m,n*k*10^(-6))*diff(besselh(m,k*10^(-6)))))*besselh(m,k.*sqrt(xx.^2+zz.^2))),m,0,10);

>>