graph mesh code help

hey i'm trying to graph this code but i get error "Z must be a matrix, not a scalar or vector."

syms x

a=1-(exp(-x/sqrt(2))/2+exp(-x/sqrt(2)));

b=exp(-x/sqrt(2))/((2+exp(-x/sqrt(2)))^2);

c=((exp(-x/sqrt(2))*(exp(-x/sqrt(2))-2)))/4*((2+exp(-x/sqrt(2)))^3);

d=(exp(-x/sqrt(2))*(((exp(-x/sqrt(2)))^2)-8*(exp(-x/sqrt(2)))+4))/24*((2+exp(-x/sqrt(2)))^4);

syms t

[X,Y]=meshgrid(-1:1.-1:1)

Z=a+(t*b)+(c*t^2)+(d*t^3)

mesh(X,Y,Z)

[Dyuman Joshi]

The increment value seems to be incorrect or a typo

[X,Y]=meshgrid(-1:1.-1:1)

Also, for using mesh(), it is necessary for the 3rd input or Z, to be a matrix.

[Chester710]

Thanks for answering

then how can i write this ?

Answer 1

[David Hill]

a=@(x)1-exp(-x/sqrt(2))./(2+exp(-x/sqrt(2)));
b=@(x)exp(-x/sqrt(2))./((2+exp(-x/sqrt(2))).^2);
c=@(x)((exp(-x/sqrt(2)).*(exp(-x/sqrt(2))-2)))./(4*((2+exp(-x/sqrt(2))).^3));
d=@(x)(exp(-x/sqrt(2)).*(((exp(-x/sqrt(2))).^2)-8*(exp(-x/sqrt(2)))+4))./(24*((2+exp(-x/sqrt(2))).^4));
Z=@(x,t)a(x)+t.*b(x)+c(x).*t.^2+d(x).*t.^3;
[x,t]=meshgrid(-1:.01:1);
mesh(x,t,Z(x,t));

[Chester710]

Thank you sir