how to convert vectore to function before integral

8 次查看（过去 30 天）
Jonathan Jubran
Jonathan Jubran 2021-5-22
回答： Sulaymon Eshkabilov 2021-5-23
im working on a project and the whole time i worked with vectors that shows the numbers of function, but now i want to integral the function, and i cant integral the vector, i cant use trapez, it give whrong unswear too.
%% Q1part1
T0=20;
T1=5;
w0=(2*pi)/T0;
x= exp(-1*abs(t));
for n=1:601
if n>100
x(n)=0;
end
end
for n=1:601
if n>200
x(n)=x(n-200);
end
end
figure(1)
plot(t,x)
xlim([-5 55])
%% Q1part3
fun = @(x,n) exp(-abs(x)-1i*x.*n.*w0);
c=[1:1:81];
t=[-40:1:40];
helper=[1:1:81];
for n=1:81
c(n) = 0;
helper(n) = 0;
helper(n) = integral(@(x) fun(x,n-41),-5,5);
helper(n)=helper(n)./20;
if abs(imag(helper(n)))<0.01
c(n)= real(helper(n));
end
end
figure(2)
plot(t,c)
%% Q1part6
figure(345345)
plot(t,x)
function [EN] = integralfor6(n,x,c)
t=linspace(-5,55,601);
x_n=0;
T0=20;
w0=(2*pi)/T0;
% X=@(t) exp(-2*abs(t))
x=x.*x
figure(8888)
plot(t,x)
for i=-n:n
x_n = x_n+(c(i+40)*(cos(i*w0*t)));
end
end

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回答（1 个）

Sulaymon Eshkabilov
Your code contains a few potential errs that have been corrected.
%% Q1part1
T0=20;
T1=5;
t=linspace(-5, 55, 601);
w0=(2*pi)/T0;
x= exp(-1*abs(t));
for n=1:601
if n>100
x(n)=0;
end
end
for n=1:601
if n>200
x(n)=x(n-200);
end
end
figure(1)
plot(t,x)
xlim([-5 55])
%% Q1part3
fun = @(x,n) exp(-abs(x)-1i*x.*n.*w0);
c=1:81;
t=-40:40;
helper=1:81;
for n=1:81
c(n) = 0;
h(n) = 0;
% helper(n) = 0;
helper(n) = integral(@(x) fun(x,n-41),-5,5);
helper(n)=helper(n)./20;
H(n) = quad(@(x) fun(x,n-41),-5,5); % Quad is also tested
if abs(imag(helper(n)))<0.01
c(n)= real(helper(n));
end
if abs(imag(H(n)))<0.01
h(n)= real(H(n));
end
end
figure(2)
plot(t,c, 'r'), title('Integral @')
figure(3)
plot(t, h, 'b'), title('Quad @')
%% Q1part6
[X,t] = integralfor6(n,x,c);
figure(4)
plot(t,X)
function [x_n,t] = integralfor6(n,x,c)
t=linspace(-5,55,601);
x_n=0;
T0=20;
w0=(2*pi)/T0;
% X=@(t) exp(-2*abs(t))
x=x.*x;
figure(5)
plot(t,x)
for i=1:n-40
x_n = x_n+(c(i)*(cos(i*w0*t)));
end
end
Note that quad() is also tested.
Good luck.

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