How do I perform a sin^2 or a cos^2 fit for my data?
5 次查看(过去 30 天)
显示 更早的评论
I have the following x data and y data:
x = [0,10,20,30,40,50,60,70,80,90,100,110,120,130,140,150,160,170,180]
y = [880,1200,1900,2700,3300,3600,3000,2100,1300,860,1200,1900,2700,3150,3300,2900,2100,1300,860]
How do I perform a cos^2 (x) or a sin^2 (x) fit for the above data?
0 个评论
采纳的回答
Star Strider
2024-5-23
Perhaps this —
x = [0,10,20,30,40,50,60,70,80,90,100,110,120,130,140,150,160,170,180];
y = [880,1200,1900,2700,3300,3600,3000,2100,1300,860,1200,1900,2700,3150,3300,2900,2100,1300,860];
LvLocs = islocalmax(y, 'MinProminence',mean(y));
xlocs = x(LvLocs)
freq = 1/mean(diff(xlocs))
[lb,ub] = bounds(y)
fcn = @(b,x) b(1).*sin(2*pi*x*b(2)).^2 + b(3);
[B,fv] = fminsearch(@(b)norm(y - fcn(b,x)), rand(3,1))
txt = sprintf('$f(x) = %.2f \\cdot sin(2 \\pi x %.3f)^2 %+.3f$', B)
figure
plot(x, y)
hold on
plot(x, fcn(B,x), '-r')
hold off
grid
xlabel('X')
ylabel('Y')
text(50, 3750, txt, 'Interpreter','LaTeX')
.
6 个评论
更多回答(0 个)
另请参阅
类别
在 Help Center 和 File Exchange 中查找有关 Get Started with Curve Fitting Toolbox 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!