Range Theta from 0 to 2Pi and plot

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james hayek 2016-9-9

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评论： james hayek 2016-9-10

Hello everybody,

I'm am looking to make a plot of numerous perpendicular components of a Transverse Electric Field. I did the general work on paper and come up with the following:

I wrote the following script in which I thought would range theata_i from 0 to Pi/2 I received help from Dr. Siva as commented below.

Using the suggestion I was able to see a range of values for both theata_i as well as theata_t

However, I do not see a range of values for the reflectedPerpendic variable. I would like to plot this range of values VS theata_i or theata_t but can not since only one value is being assigned to the variable "reflectedPerpendic"

How can I write this to an array? I tried adding brackets. I also tried appending a (i) to the variable as such: reflectedPerpendic(i) to add it to an array element, but that didn't work.

Maybe I have to use a for loop, if so, I am not sure of the approach to take.

The code is as follows:

% James Hayek
% 
% Setting up the variables for the parameters
n1 = 1;
n2 = 1.5;
% We are looking to range theata_i from 0 t 90 degrees
% For now, we will use a constant value and then range as we finialize the
% script
theata_i = linspace(0,pi/2,50)
% The value of theata_t as per Snells Law
theata_t = asin((n1/n2)*(sin(theata_i)))
% The function as derived from HW1 ii section a
reflectedPerpendic = (n1*cos(theata_i) - n2*cos(theata_t))/(n1*cos(theata_i) + n2*cos(theata_t))
% Using the plot function
plot(abs(theata_t), abs(reflectedPerpendic),'x')

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Answer 1

Les Beckham 2016-9-9

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https://ww2.mathworks.cn/matlabcentral/answers/302446-range-theta-from-0-to-2pi-and-plot#answer_234315

在 MATLAB Online 中打开

Change the divide in your equation for reflectedPerpendic to an element-by-element divide as follows:

reflectedPerpendic = (n1*cos(theata_i) - n2*cos(theata_t))./(n1*cos(theata_i) + n2*cos(theata_t))

Note the use of './' instead of '/'. Without the '.' you are doing a vector divide, the result of which is a scalar.

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james hayek 2016-9-10

This community is amazing, thanks for all the help!! Everything works as expected, thanks again,

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Answer 2

KSSV 2016-9-9

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/302446-range-theta-from-0-to-2pi-and-plot#answer_234257

You may consider using

theta = linspace(0,2*pi,N) ; % where N is number of points you want.

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james hayek 2016-9-9

编辑：james hayek 2016-9-9

Thanks, that worked quite well. But looks like I have another problem:

In terms of the "reflectedPerpendic" variable, This only places one value into the variable reflectedPerpendic I would love to find a way to write all elements to an array and plot each of those values found. Brackets didn't work, and I couldn't think of how using a FOR loop. With that aside, I didn't need a for loop for the variables theata_i and theata_t

How come I don't see a range of values for "reflectedPerpendic"?

Any ideas?

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