help with analysis of equations

Question

jessica 2013-7-24

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/82978-help-with-analysis-of-equations

if true
fplot('x^2-5*x*sin(3*x)+3',[0,10]);
disp('positive roots of the equation are')
x1=fzero('x^2-5*x*sin(3*x)+3',2)
x2=fzero('x^2-5*x*sin(3*x)+3',2.7)
end

determine the positive roots of the equation

x^2-5*x*sin(3*x)+3

    2.3656
    2.8435

I keep getting this two and my book says there should be 4 3.8;3.4;1.8;1.3

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Answer 1

Narges M 2013-7-24

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/82978-help-with-analysis-of-equations#answer_92604

在 MATLAB Online 中打开

Try this:

if true
   fplot('x^2-5*x*sin(3*x)+3',[0,10]);
   disp('positive roots of the equation are')
   hold on;
   plot(0:10,zeros(1,11), '--c');
   x1=fzero('x^2-5*x*sin(3*x)+3',2)
   x2=fzero('x^2-5*x*sin(3*x)+3',2.7)
   plot(x1,0,'rX', 'MarkerSize',8);
   plot(x2,0,'rX', 'MarkerSize',8);
end