How do I create a phase plot?

I'm trying to plot two functions I have defined against each other but I am not getting the result I should be getting. The functions are

y=exp(-1/16*x)*(2*cos(sqrt(1023)/16*x)-382/sqrt(1023)*sin(sqrt(1023)/16*x))+12*sin(2*x)

and

y'=-1/16*exp(-1/16*x)*(2*cos(sqrt(1023)/16*x)-382/sqrt(1023)*sin(sqrt(1023)/16*x))+exp(-1/16*x)*(-sqrt(1023)/8*sin(sqrt(1023)/16*x)-382/16*cos(sqrt(1023)/16*x))+24*cos(2*x)

and I'm trying to create a plot of y' vs y.

I've tried the following code

f = @(x) -1/16*exp(-1/16*x)*(2*cos(sqrt(1023)/16*x)-382/sqrt(1023)*sin(sqrt(1023)/16*x))+exp(-1/16*x)*(-sqrt(1023)/8*sin(sqrt(1023)/16*x)-382/16*cos(sqrt(1023)/16*x))+24*cos(2*x);
g = @(x) exp(-1/16*x)*(2*cos(sqrt(1023)/16*x)-382/sqrt(1023)*sin(sqrt(1023)/16*x))+12*sin(2*x);
fplot(g,f)

and I get a plot that looks like this.

But according to the assignment the plot should look like this.

Answer 1

[KSSV]

You would have messed up with derivative of y. Check symbolic differentiation. You enter y, let matlab do derivative for you and then plot. Check symbolic calculations in matlab

Answer 2

[Mahak Nischal]

need help in plotting beam phase profile of optical beam having phase a*exp(-phi*1i) where a is the amplitude?