Problem with radians and degrees

Question

Luccas S. 2021-4-29

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/817325-problem-with-radians-and-degrees

评论： Luccas S. 2021-4-29

I am implementing this code. And the result does not match at all. The result must be in radians and the result must be the following:

sigma (1) = -0.247

omega (1) = 0.966

sigma (2) = -0.494

omega (2) = 0 ~ very small number almost zero

sigma (3) = -0.247

omega (3) = -0.966

I found this on the calculator (in radians). But the program doesn’t match at all

% Chebshevy Poles
    clc
    clear
    
    n = 3; % filter order
    ripple = 1; % dB
    epsilon = sqrt(10^(0.1*ripple)-1)
    a = (1/n)*asinh(1/epsilon)
    
    
    for k = 1:1:n
    sigma(k) = -sinh(a)*sin(((2*k-1)/2*n)*pi);
    omega(k) = cosh(a)*cos(((2*k-1)/2*n)*pi);
    end

The value of this a is 0.476

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Answer 1

the cyclist 2021-4-29

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/817325-problem-with-radians-and-degrees#answer_688255

在 MATLAB Online 中打开

You need parentheses around 2*n. Otherwise, MATLAB will divide by 2, then multiply by n.

% Chebshevy Poles
    clc
    clear
    
    n = 3; % filter order
    ripple = 1; % dB
    epsilon = sqrt(10^(0.1*ripple)-1);
    a = (1/n)*asinh(1/epsilon);
    
    
    for k = 1:1:n
    sigmak(k) = -sinh(a)*sin(((2*k-1)/(2*n))*pi);
    omegak(k) = cosh(a)*cos(((2*k-1)/(2*n))*pi);
    end
    
    disp(sigmak)
   -0.2471   -0.4942   -0.2471
    disp(omegak)
    0.9660    0.0000   -0.9660