Domain sketch for multiple variables function

4 次查看（过去 30 天）
Nhi Nguyen
Nhi Nguyen 2021-7-7
回答： Walter Roberson 2021-7-7
How do I sketch the domain of the function f(x,y) = ln(9 - x^2 - 9y^2)?
This is for my exercise so I really need some help. Thanks in advanced!

请先登录，再回答此问题。

采纳的回答

Walter Roberson
Walter Roberson 2021-7-7
Ran in:
For example
expr = @(x,y) -x.^2 - 2.*x.*y - 7.*y.^2 + 11.*y + 1;
[X,Y] = meshgrid(linspace(-5,5,200));
eZ = expr(X,Y);
eZ(eZ<=0) = nan;
Z = log(eZ);
surf(X, Y, Z, 'edgecolor', 'none')
xlabel('x'); ylabel('y')
[r,c] = find(~isnan(eZ),1)
r = 124
c = 30
[X(r,c), Y(r,c), eZ(r,c), Z(r,c)]
ans = 1×4
-3.5427 1.1809 0.0446 -3.1101

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Surface and Mesh Plots 的更多信息

标签

产品


版本

R2018a

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by