Average value and RMS value

8 次查看（过去 30 天）
David Perez Ramos
回答： Star Strider 2015-3-2
Hello, I am trying to verify functions taking the average and RMS value using trapz function,but I am not getting the right answer in matlab. according to the theory in the book the average value of a function is obtained by: 1/(b-a)∫〖5sin(t)〗, across the interval a<t<b. This is what I have done:
EDITOR:
%Verify that the average value for F(t)=5sin(t), is zero.
%Verify that the RMS value for F(t)=5sin(t), is 3.535.
function z= myfun2(t)
a = 1;
b = 3;
z =(1/b-a)*(5*sin(t)); %function for average value.
end
COMMAND WINDOW:
>> t = linspace(1,3,400);
>> z = myfun2(t);
>> average = trapz(t,z)
average =
-5.1010
When I do it by hand, I do get zero for the average value, but in matlab and dont get zero. Is something wrong in my z function?

请先登录，再回答此问题。

采纳的回答

Star Strider
Star Strider 2015-3-2
I’m guessing at what your problem actually says, but the problem may be the ‘a’ and ‘b’ limits. Adding pi to them as a factor, and correcting the definition of mean value:
myfun2 = @(t) 5*sin(t);
a = pi;
b = 3*pi;
t = linspace(a,b,400);
z = myfun2(t);
average = trapz(t,z)./(b-a)
produces:
average =
-95.6651e-018
which is essentially zero to floating-point precision.
The mean value is Integral(f(t),a,b)/(b-a).

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Numerical Integration and Differentiation 的更多信息

标签

Community Treasure Hunt

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

Start Hunting!

Translated by