Taylor Series figure problem

Consider the following expression:

f(x)= x^2 sin(x)+e^-x * cos^2 (x)

Plot varying 'x' from '-π' to '+π' for 100 points.

Using Taylor's series expansion for of degree 4, plot the graph with the above graph using hold on feature for same range of x.

Add Taylor series of degrees 7 and 10 to the same plot.

Compare the results. In the graph, add legend, title, axis titles. Add different line style, markers, colors. Choose appropriate font size for the graph.

this is my code and I got two figures but one of them is not the true solution which is the first figure so can you please help?

xx= linspace(-pi,pi, 100);
syms x
fx=(x*x^2)*sin(x*x)+exp(-x*x)*(cos(x*x)^2);
figure(1)
fplot(xx,fx, 'linewidth' ,2)
title('Original Signal')   
xlabel('x')
ylabel('f(x)')

f= (x^2)*sin(x)+exp(-x)*(cos(x)^2);
T4 = taylor(f,x, 'Order',4);
figure (2)
fplot(T4,[-pi pi],'--') 
hold on;
T7 = taylor(f,x,'Order', 7);
fplot(T7,[-pi pi],'-o')
T10 = taylor(f,x, 'Order', 10); 
fplot(T10,[-pi pi],'-')
legend('Degree = 4','Degree = 7', 'Degree = 10') 
xlabel('x')
ylabel('f(x)')
title('Taylor Series Approximation')

Answer 1

[Dyuman Joshi]

The first function definition is incorrect

xx = linspace(-pi,pi, 100);
syms x
%function definition
f(x)=(x^2)*sin(x)+exp(-x)*(cos(x)^2);
%You can use the same definition for the whole code
figure(1)
plot(xx,double(f(xx)),'linewidth',2)
xlim([-pi pi])
title('Original Signal')   
xlabel('x')
ylabel('f(x)')

T4 = taylor(f,x,'Order',4);
figure (2)
fplot(T4,[-pi pi],'--') 
hold on;
T7 = taylor(f,x,'Order',7);
fplot(T7,[-pi pi],'-o')
T10 = taylor(f,x, 'Order',10); 
fplot(T10,[-pi pi],'-')
legend('Degree = 4','Degree = 7', 'Degree = 10') 
xlabel('x')
ylabel('f(x)')
title('Taylor Series Approximation') 

Answer 2

[Walter Roberson]

Your fplot syntax was wrong.

xx= linspace(-pi,pi, 100);
syms x
fx=(x*x^2)*sin(x*x)+exp(-x*x)*(cos(x*x)^2);
figure(1)
fplot(fx, [-pi pi], 'linewidth' ,2)
title('Original Signal')   
xlabel('x')
ylabel('f(x)')

f= (x^2)*sin(x)+exp(-x)*(cos(x)^2);
T4 = taylor(f,x, 'Order',4);
figure (2)
fplot(fx, [-pi pi], 'linewidth' ,2)
hold on
fplot(T4,[-pi pi],'--') 
T7 = taylor(f,x,'Order', 7);
fplot(T7,[-pi pi],'-o')
T10 = taylor(f,x, 'Order', 10); 
fplot(T10,[-pi pi],'-')
legend({'origina', 'Degree = 4','Degree = 7', 'Degree = 10'}) 
xlabel('x')
ylabel('f(x)')
title('Taylor Series Approximation')