how to plot y=|x| function without using abs,

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rivaldo rivaldo 2016-12-3

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https://ww2.mathworks.cn/matlabcentral/answers/315192-how-to-plot-y-x-function-without-using-abs

评论： bio lim 2016-12-3

hi im trying to plot two functions the first y=|x| the second y=|x+4|-|x^2-7| without abs func but with for and if please help thanks

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James Tursa 2016-12-3

What have you done so far? What specific problems are you having with your code?

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bio lim 2016-12-3

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在 MATLAB Online 中打开

Well you have to find the regions where your values of y are positive and negative. Here is an example of y = |x|.

x = -100:100;
for i = 1:length(x)
    if x(i)<0
        y(i) = -x(i);
    else y(i) = x(i);
    end
end

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rivaldo rivaldo 2016-12-3

在 MATLAB Online 中打开

clear all;close all;clc

x = -10:0.01:10;

for i = 1:length(x)

if x(i)+4>0

 y(i)=-x(i)+4;
    else y(i) = -x(i)-4;
    end
    for j=1:length(x)
        if x(j).^2+7>0
            g(j)=x(i).^2+7;
        else g(j)=-x(i).^2-7;
        end

end

plot(x,y)

hold on

plot(x,g)

bio lim 2016-12-3

在 MATLAB Online 中打开

x = -10:0.01:10;
% let's call a = |x+4|
%            b = |x^2 - 7|
for i = 1:length(x)
    if (x(i)+4<0)
        a(i) = -(x(i)+4);
    else a(i) = x(i)+4;
    end
end
for i = 1:length(x)
    if (x(i)^2-7<0)
        b(i) = -(x(i)^2 -7);
    else b(i) = x(i)^2 -7;
    end
end
y = a - b;