create the symbolic expression shown then use the subs command to evaluate the expression for x = 4. save the final value as y_value with the class 'double'. y= 5x^4-2x/x^2-1 in matlab

To create the symbolic expression in MATLAB, you can use the syms function to define the symbol x, and then use arithmetic operators to create the expression. Here's how you can create the symbolic expression y = 5x^4 - 2x / x^2 - 1:

main.m
syms x
y = 5*x^4 - 2*x / (x^2 - 1);
36 chars
3 lines

To evaluate the expression for x = 4, you can use the subs command by passing the expression and the value of x as arguments. The output will be a symbolic representation of the evaluated expression:

main.m
x_value = 4;
y_evaluated = subs(y, x, x_value);
48 chars
3 lines

If you want to save the final value as a double, you can use the double command to convert the symbolic expression to a double:

main.m
y_value = double(y_evaluated);
31 chars
2 lines

Now, y_value will contain the evaluated value of the expression for x = 4 in double precision.

Remember to have the Symbolic Math Toolbox installed in order to use symbolic expressions in MATLAB.