Evaluating the area between two curves.
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how to Evaluate the area between two curves using matlab? for example this one y=x^2 and y=2*x
2 个评论
kalash vasaniya
2021-11-8
Find the area of the region bounded by the curves x=y^3 and x=y^2 in matlab
syms x y
fimplicit([x == y^3, x == y^2], [-1 10])
Which of the two areas? The right-hand one is obviously unbounded, but your instructions do not say to do only the other area.
And please explain how your instructions will solve the question asked 10 years ago by Ejay Kasai ??
回答（2 个）
Grzegorz Knor
2011-9-12
In your case:
syms x
x0 = eval(solve('x^2 -2*x'));
x = linspace(x0(1),x0(2),100);
y1 = x.^2;
y2 = 2*x;
fill([x x(end:-1:1)],[y1 y2(end:-1:1)],'r')
hold on
plot(x,y1,x,y2,'LineWidth',2)
grid on
a = trapz(x,y2)-trapz(x,y1);
Instead of:
syms x
x0 = eval(solve('x^2 -2*x'));
You can use:
x0(1) = fzero('x.^2 -2*x',1);
x0(2) = fzero('x.^2 -2*x',1.5);
6 个评论
Ejay Kasai
2011-9-12
Oleg Komarov
2011-9-12
So, you're not happy with "a"?
Ejay Kasai
2011-9-12
Oleg Komarov
2011-9-12
Grzegorz has given you a valid solution. If you really needed the value you wouldn't have posted the comment in the first place since it's in the code.
Ejay Kasai
2011-9-13
Walter Roberson
2011-9-13
The expression Grzegorz gave, a = trapz(x,y2)-trapz(x,y1) *is* the code to evaluate the area between the two curves. This is elementary calculus: the area between two curves is the difference between their integrals. trapz() calculates numeric integrals.
Shyam babu
2023-7-8
0 个投票
find the area included between the curves y^2=4*x & x^2=4*y
1 个评论
Walter Roberson
2023-7-8
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2011-9-12
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