Quadratic integration coding error

The code I have done as shown below is the trapezoidal integration of the functions. I am having some an issue of the quad function to accept the function y to be accepted.

if true
  % code
x = t;
t = 0:0.1:10; 
for c= 0.1;
  y1 = t.*sin(c.*t);
  A= trapz(x,y1)
  a= quad(@y,0,10)
  for c2 = 10*pi;
      y2= t.*sin(c2.*t);
      A2 = trapz(x,y2)
      for c3 = 200
          y3= t.*sin(c3*t);
          A3 = trapz(x,y3)
      end
  end
end

end

Answer 1

[ChristianW]

The trapz inputs are just points. But quad needs a function as input.

x = 0:1:10;
y = sin(x);
A_trapz = trapz(x,y)

f = @(z) sin(z); % y = f(z) = sin(z)
A_quad = quad(f,x(1),x(end))

Answer 2

[Youssef Khmou]

hi,

like the answer above, quad takes function handle as input, while trapz accepts vectors , but the way you wrote the loops is incorrect , beside you do not need loops :

   % RANGE
t = 0:0.1:10; 
x = t;
%Constants
c= 0.1;
c2 = 10*pi;
c3 = 200;

 %1) Function Handle and vector
 Y1=@(t) t.*sin(c.*t); 
 y1= t.*sin(c.*t);

 %2) Function Handle and vector
 Y2=@(t) t.*sin(c2.*t);
 y2= t.*sin(c2.*t);

 %3) Function Handle and vector
 Y3=@(t) t.*sin(c3.*t);
 y3= t.*sin(c3.*t);

 %INTEGRALS 

 A1=quad(Y1,0,10);
 a1=trapz(x,y1);

 A2=quad(Y2,0,10);
 a2=trapz(x,y2);

 A3=quad(Y3,0,10);
 a3=trapz(x,y3);

 % FIGURE

 figure, plot([c c2 c3],[A1 A2 A3])
 hold on, plot([c c2 c3],[a1 a2 a3],'r')
 legend(' USING QUAD','USING TRAPZ')
 hold off, xlabel(' constants ci'),
 ylabel(' Integrals magnitude');