problem in functin (y for x)

Question

Lila wagou 2017-3-1

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编辑： Stephen23 2017-3-1

Hy i have a problem in the flowing code (XZData.m function)

function [x,y] = XZData(A,B,C)
x = 0:1:10;
y = (A*x^2)+(B*x)+C;
XY = ['XData', num2str(x), 'yData', num2str(y)];
disp(XY)

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Answer 1

Star Strider 2017-3-1

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编辑：Stephen23 2017-3-1

在 MATLAB Online 中打开

Use element-wise exponentiation in the ‘y’ assignment:

y = (A*x.^2)+(B*x)+C;
        ↑ ← INSERT ‘.’ HERE
function [x,y] = XZData(A,B,C)
x = 0:1:10;
y = (A*x.^2)+(B*x)+C;
XY = ['XData ', num2str(x), ' yData ', num2str(y)];
disp(XY)
end

See the documentation on Array vs. Matrix Operations for details.

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Answer 2

Walter Roberson 2017-3-1

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Use x.^2 with the dot instead of x^2

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Answer 3

John D'Errico 2017-3-1

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https://ww2.mathworks.cn/matlabcentral/answers/327576-problem-in-functin-y-for-x#answer_256863

编辑：John D'Errico 2017-3-1

在 MATLAB Online 中打开

It makes it easier to get help if you report the (COMPLETE) error message that you got. Help those who would help you.

In this case though, the problem is that you need to learn about the elementwise operators, like .* ./ and .^ , since that is where your immediate problem arises.

Change the computation of y to this:

y = (A*x.^2)+(B*x)+C;

x is a vector. You wish to compute the square of each element of x, so use the .^ operator.

Admittedly, I think your next problem is that you won't like how that line gets displayed in the call to disp. It will be one long line of text. But that is for you to decide.