double integral and fitted functions

Hi guys,

I have two fitted functions a(t)and b(t). Both via splines. I need to compute an integral:

integral(func,0,1)

where func=a(u)*integral(b(t),0,u).

I know that I can do integrate(cf,0,1) for a fitted object. But how can I compute a double integral?

Thanks.

Daniel.

[Daniel]

Pleease, help me!

Answer 1

[Mike Hosea]

I'm going to treat this like a homework problem. You'll need to define some anonymous functions. For example, if b is a pp-form, you can create a function that evaluates b by

bfun = @(x)ppval(b,x);

and

bint = @(u)integral(bfun,0,u);

Then you can build up to the point where you can define func. There's more to know, e.g. about "vectorizing" bint with ARRAYFUN before using it, or choosing the 'Arrayvalued' option in the outer integral. You can find some threads on that. But first you need to get started by understanding how to define anonymous functions in MATLAB.