MATLAB: Error + matrix dimension must agree

matrix

I got error — Error using + Matrix dimensions must agree.

on this code. Please help me

    a=sign(X(ind1)).*(abs(X(ind1))-T);
    b=abs(X);
    c=plus(a,b);

Nik, X and T need to be same-sized vectors unless T is a scalar.

What are you trying to do in

 a = sign(X(ind1)).*(abs(X(ind1))-T);

especially w.r.t. T?

fp = (1./(x + h) - 2*(1/x) + 1./(x - h)) ./h.^2;

x=1:42
c = 2*x+1

more :)

c = zeros(1,42);
for x = 1:42
    a = x;
    b = a + 1;
    c(x) = a + b;
end

more 2

x=1:42
c = zeros(size(x));
for i1 = 1:numel(x)
    if x(i1) == i1
        a = x(i1);
        b = a + 1;
    end
    c(i1) = a + b;
end