# What am I doing wrong here? I am trying to recreate following highlighted equations in the table.

2 views (last 30 days)
Nissal Arachchige on 26 Mar 2021
Commented: Paul Hoffrichter on 28 Mar 2021  ep = linspace(0,1);
m1 = 1.5; m2 = 3.8;
ep0= 1; alpha = 0.785; epp = 0.11;
qep = (2.76*ep*cosh((3*ep)-1.92));
I1 = ep.^ m1;
I2 = ep.^ m2;
I3 = ep*((ep-epp)/(ep0-epp)).^alpha;
I6 = 1-(qep*((3*(1-ep))/(3-ep)));
Hold on
plot(ep,I1)
plot(ep,I2)
plot(ep,I3)
plot(ep,I6)
Hold off

Paul Hoffrichter on 27 Mar 2021
Edited: Paul Hoffrichter on 27 Mar 2021
clc; clear; clf
ep = linspace(0,1);
m1 = 1.5; m2 = 3.8;
ep0= 1; alpha = 0.785; epp = 0.11;
qep = (2.76*ep.*cosh((3*ep)-1.92));
I1 = ep.^ m1;
I2 = ep.^ m2;
zz = (ep-epp)/(ep0-epp);
zza = zz .^ alpha; % zza is complex
I3 = ep .* zza;
I6 = 1-(qep*((3*(1-ep))/(3-ep)));
hold on
plot(ep,I1);
plot(ep,I2)
plot(ep,I3) % This is Line 18 - usually do not plot a complex vector like this
plot(ep,I6)
hold off
warning:
Warning: Imaginary parts of complex X and/or Y arguments ignored.
> In Untitled (line 18) Paul Hoffrichter on 28 Mar 2021
I was a surprised at first about the complex numbers. But then I thought about what if alpha was 0.5 instead of 0.785. Then if x is a negative number, we have a purely imaginary result for x^(.5)=sqrt(x)= sqrt{(-1) * abs(x)} = 0 + j*sqrt(abs(x)). For other values of alpha between (0.5, 1.0), we get complex numbers. ### Categories

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