HOW TO GET THE VALUES OF CONSTANTS

syms y(x)
pi=3.14;
ode = diff(y,x,2) == 0;
ySol(x) = dsolve(ode)



THE ANSWER COOMING IS ySol(x) =
 
C2 + C1*x

IF I HAVE CONDITIONS 
ysol(0)=0 and ySol(pi)=0 how to get the values of c1 and c2

Answer 1

[John D'Errico]

Please don't YELL!

Next, NEVER define pi. pi already exists, and I hate to tell you, it ain't 3.14. That only happens in certain places I won't name. In MATLAB, pi is already defined, far more accurately than that.

format long g
pi

ans = 
          3.14159265358979

syms y(x)
ode = diff(y,x,2) == 0;
ySol(x) = dsolve(ode,y(0) == 0,y(pi) == 0)

ySol(x) = 

0

Which is what you would expect, since if we have the ODE with no boundary conditions at all,

y'' == 0

the general solution is as you found, a linear polynomial. If that polynomial must then be zero at two points, then the polynomial reduces to the constant value 0.