Help with plotting following equation.

Quite new to Matlab and I am facing some trouble. Kindly, help.

syms B1(x) Q(x) p0x(x) a1(x) u0(x,y) v0(x,y) b1(x) c1(x) c2(x) c3(x) M(x,y) f1(x) f2(x) f3(x) L N(x,y) x1(x) x2(x) x3(x) x4(x) K(x) u(x,y)
B1(x) = 1 + 0.3*cos(2*pi*x);
Q(x) = (sinh(sqrt(1000)*B1(x))-sqrt(1000)*B1(x)*cosh(sqrt(1000)*B1(x))) ;
p0x(x) = 1/Q(x);
a1(x) = p0x(x)/cosh(sqrt(1000)*B1(x));
u0(x,y) = -p0x(x) + a1(x)*cosh(sqrt(1000)*y);
v0(x,y) = y*diff(p0x,x) -diff(a1,x)*sinh(sqrt(1000)*y)/sqrt(1000);
b1(x) = -diff(p0x,x)*B1(x) + diff(a1,x)*sinh(sqrt(1000)*B1(x))/sqrt(1000);
u1(x,y) = c1(x)*cosh(sqrt(1000)*y)+c2(x)*sinh(sqrt(1000)*y)+c3(x)+M(x,y);
M(x,y) = (1/2000)*((f1(x)*y*sinh(sqrt(1000)*y)/(2*sqrt(1000)))-((f2(x)/1000)*(4-(L^2)*1000*(y^2)-2*L^2))+f3(x)*y/1000);
f1(x) = 2000*(L^2 - 2)*diff(a1,x,2) ;
f2(x) = 1000*diff(p0x,x,2);
f3(x) = 2*(L^2)*(1000^2)*diff(b1,x);
N(x,y) = diff(M,y) ;
x1(x) = sqrt(1000)*B1(x)*sinh(sqrt(1000)*B1(x)) ;
x2(x) = (1000)*B1(x)*M(x,B1(x)) ;
x3(x) = sqrt(1000)*(sqrt(1000)*B1(x)*cosh(sqrt(1000)*B1(x))-sinh(sqrt(1000)*B1(x)));
x4(x) = sqrt(1000)*M(x,B1(x))*sinh(sqrt(1000)*B1(x));
c1(x) = (1/x3(x))*((K(x)*(1000))+N(x,0)-(N(x,0)*cosh(sqrt(1000)*B1(x)))+x1(x)-x2(x));
c2(x) = -(N(x,0)/sqrt(1000));
c3(x) = (-1/x3(x))*((K(x)*(1000)*cosh(sqrt(1000)*B1(x)))+N(x,0)-(N(x,0)*cosh(sqrt(1000)*B1(x)))+x4(x));
K(x) = (1/2000)*(((f1(B1(x)))/2000)*(B1(x)*cosh(sqrt(1000)*B1(x))-sinh(sqrt(1000)*B1(x)))-((f2(B1(x))/1000)*(4*B1(x)-(L^2)*1000*(B1(x)^3)/3)-2*(L^2)*B1(x))+(f3(B1(x))*B1(x)^2)/2000);
u(x,y) = u0(x,y) + (0.3*0.3)*u1(x,y);
L=2;
y = -1.3:0.1:1.3;
plot(y,u(0,y))

[KSSV]

Try fplot. Or substitute the values using subs and use plot.