fix typo

dynare++/doc/dynare++-tutorial.tex

@@ -70,7 +70,7 @@ preamble follows:
 var Y, C, K, A, H, B;
 varexo EPS, NU;
 
-parameters beta, rho, beta, alpha, delta, theta, psi, tau;
+parameters beta, rho, alpha, delta, theta, psi, tau;
 alpha = 0.36;
 rho   = 0.95;
 tau   = 0.025;