Matlab - Ayuda para realizar el gráfico de una función

clear

syms x

y=3.5^(-0.5*x)*cos(x);

h1=0.2; h2=0.05;

X1=-2:h1:4;  X2=-2:h2:4;

FX1=subs(y,x,X1);

FX2=subs(y,x,X2);

plot(X1,FX1,'r', X2,FX2,'b')

xlabel('X1 , X2')

ylabel('FX1 , FX2')

legend('FX1','FX2')

title (char(y))

clear

syms x

p=9-7*x+5*x^2-3*x^3+2*x^4;

dp=diff(p);

ip=int(p);

X=-2*pi:0.1:2*pi;

P=subs(p,x,X);

DP=subs(dp,x,X);

IP=subs(ip,x,X);

plot(X,P,'r', X,DP,'b', X,IP,'m')

xlabel('X')

ylabel('P  ,  DP,  IP')

legend('Polinomio','Su derivada', 'su integral')

title (['p(x)=',char(p)])

grid on