why its giving error? Its saying cant read A1(2.3), its not logical

   t = 1:9;

   t1 = 1 : 0.1 :9;

   A = [916.3, 923.6, 933.1, 947.4, 966.2, 986.6, 1008.5, 1031.5, 1051.3];

   A1 = interp1(t ,A , t1) ;

   a= 1;

   b=9;

   h= 1.3;

   for i = 0:3

   res = 0.5*[A1(a+ i*h)+ A1(a + (i+1)*h)]*h

   disp('res')

   end

Answer 1

[ES]

all Indices in matlab must be positive integers. your h is 1.3 so for all i values it will try to access A1(i.3) which is not correct.

    res = 0.5*[A1(a+ i*h)+ A1(a + (i+1)*h)]*h

It might help if you say what you ant to achieve in your code. For example

disp('res')

will not give you desired results. It should be

disp(res)

instead.

[Rizwana]

when it shows A1(2.3) how should i code it so that it reads 2nd columns 3 rd reading?

[ES]

>> size(A1)

ans =

       1    81

A1 is a single dimensional array. It has one row and 81 columns. What do you mean by 2nd columns 3 rd reading?

[Rizwana]

My mistake. I want to excess 23(2.3) column now. Dont know how to do it. Will try arranging my data in 2D array. If i get stuck again will get back to you. Thank You

Answer 2

[sidra]

Reading up about matrix indexing will be helpful in your case. Try the link below:

http://www.mathworks.com/help/matlab/math/matrix-indexing.html

[Rizwana]

Yeah started reading it. Thank You