Plotting graph using roots
8 次查看(过去 30 天)
显示 更早的评论
I have calculated the roots of ? = ? 3 + 5.5? 2 + 3.5? − 10 (p=[1 5.5 3.5 -10]; >> x=roots(p) x = -4.0000 -2.5000 1.0000) How do I plot this on a single graph (The curve y for −5 ≤ ? ≤ 3.). Any help will be appreciated:)
0 个评论
采纳的回答
ME
2019-12-13
The roots you have calculated are the x values where y = 0. Therefore to plot these on a graph you can use:
p = [1 5.5 3.5 -10];
x = roots(p);
xaxis = -5:0.1:3;
y= xaxis.^3 + 5.5.*xaxis.^2 + 3.5.*xaxis - 10;
plot(xaxis,y,'-',x,zeros(size(x)),'o');
This shows the curve of the function over your specified interval and then plots circles at the roots you have obtained to highlight their location on the plot.
4 个评论
Steven Lord
2019-12-13
One suggestion: since you already have the coefficients of the polynomial stored as the vector p, you could simplify the code that evaluates y by using polyval to evaluate the polynomial for your xaxis values. That way there's only one place where the polynomial is defined, and you'll avoid potential confusion if you change p but forget to change the line where you evaluate the polynomial and so see mismatched results.
更多回答(0 个)
另请参阅
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!