Using a vector input in integral function.

Let's say I have a function "myfun" of variable x and its integral:

myfun = @(x) x; % A continuous function of variable x (exist for any x value between integration limit, 1 to 5)
myfunint = integral(myfun,1,5); % integration between x=1 and x=5

Now I have a vector which is also a function of this same variable x (but it's a vector!)

myvec= [0.5 1.5 2.5 3.5 4.5]; % values corresponding to x = 1,2,3,4,5

and my new function "myfunnew" is a multiplication of myvec with myfun..something like

myfunNew = @(x) myvec(x).*x; % Not continuous because myvec(x) only exists for certain x values (x=1,2,3...5) and not for values inbetween.
myfunNewint = integral(myfunNew,1,5)

and I want to use integral function on myfunNew.

But it won't work because "myvec" is a vector and "myvec(x)" doesn't exist for a lot of values of x between 1 and 5 that may be required by integral function when it evaluates integral. So my question is:

• How can I convert this vector "myvec" to a continuous function (preferably using linear interpolation for missing values) so that I can use it in "myfunNew" such that it becomes integrable.

I can not use trapz.

[madhan ravi]

Why not use ArrayValued option to true?

[fizzy]

Because that's not what I need. The result of integration, myfunNewint, will be a single value.

Answer 1

[Alan Stevens]

Like this?

X = 1:5;
myvec= [0.5 1.5 2.5 3.5 4.5]; % values corresponding to x = 1,2,3,4,5
vec =@(x) interp1(X,myvec,x);  % linear interpolation

myfunNew = @(x) vec(x).*x; 
myfunNewint = integral(myfunNew,1,5)

[fizzy]

Exactly! This is so simple. I guess I wasn't using the correct words in google search