plot() and fplot() give different results for the same function
조회 수: 12 (최근 30일)
이전 댓글 표시
I'm trying to plot the function
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1617828/image.png)
between 0 and 100 (not including zero of course), but am running into a problem. When I use
x = linspace(0, 100, 10000);
y = 2.*sqrt(1+x)+((sin(sqrt(x).*pi).*sin(sqrt(1+x).*pi).*(2.*x+1))/(sqrt(x))) - 2.*sqrt(1+x).*cos(sqrt(x).*pi).*cos(sqrt(1+x).*pi);
plot(x,y);
I don't get the result I expected, which is the graph occasionally intersecting y = 0. However, by doing
fplot(@(x) 2.*sqrt(1+x)+((sin(sqrt(x).*pi).*sin(sqrt(1+x).*pi).*(2.*x+1))/(sqrt(x))) - 2.*sqrt(1+x).*cos(sqrt(x).*pi).*cos(sqrt(1+x).*pi), [0 100]);
I do get the result I expected.
I can't just use fplot, as I do need to use the variable y for other things, so I'm not sure what to do or what is even happening here. Any help would be greatly appreciated.
댓글 수: 0
채택된 답변
추가 답변 (1개)
Torsten
2024년 2월 15일
편집: Torsten
2024년 2월 15일
x = linspace(0, 100, 10000);
y = 2*sqrt(1+x)+sin(sqrt(pi)*x).*sin(sqrt(1+x)*pi).*(2*x+1)./sqrt(x) - 2*sqrt(1+x).*cos(sqrt(x)*pi).*cos(sqrt(1+x)*pi);
plot(x,y);
hold on
f = @(x)2*sqrt(1+x)+sin(sqrt(pi)*x).*sin(sqrt(1+x)*pi).*(2*x+1)./sqrt(x) - 2*sqrt(1+x).*cos(sqrt(x)*pi).*cos(sqrt(1+x)*pi);
fplot(f,[0 100])
댓글 수: 1
Bruno Luong
2024년 2월 15일
편집: Bruno Luong
2024년 2월 15일
I believe fplot ezplot replace "*" "/" "^" etc... with elementwise operators ".*" "./', ".^". It interprets as standard math notation.
This how charming or quirking MATLAB is, depending on your taste.
참고 항목
카테고리
Help Center 및 File Exchange에서 Line Plots에 대해 자세히 알아보기
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!