??? Error using ==> plot Conversion to double from sym is not possible...help?

clc
clear all

Pc=1.6*10^9
Pa=300*10^9
Ps=1*10^9
r=5
h=1
d0=0.4
 d=1:10:30

s=(d./r)
 w1=4.3
 E0=8.85*10^-12
Eb=6.830890.*(w1.^(3/2))
A1=d.^2
B1=(d./d0).^(1/3) 
 l=(0.5.*E0.*Eb.^2./B1.^2).*10^18
m=Pc
n=(4.*Pa./(1+s).^4)
x2=min(m,n)
Es=min(x2,l)

Ea= (Es.*(d+r).^2)./(2.*r.^2)
y1= (0.5.*Ea.^2.*d.^2)./((d+r).^2.*d.^3)
syms y
b=y.^2
y2= int(b,r,r+d)

u=y2
plot(d,u)

Answer 1

[Alberto]

It´s not clear what you are trying to do, but there are some bad things here:

1) when you use int command, you dont give the integration variable; i think it will be y.

2) the upper r+d is not a value, but an array. So u better write it like this:

y2= int(b,y, r,r+d(1))

( or some other selection in the array d), instead of yours :

y2= int(b,r,r+d)

By the way, you are using plot for representing 3 2D points (I hope you know that), but they cant barely be visible. You better use:

plot(d,u, 'x')

I hope this will be helpful.