Determine unknown integral limits

Dear all,

I calculated the integral from x(1) to x(end) of a given function as fellow:

syms a1 a2

Int1=quad(@ppval,x(1),x(end),[],[],pp)

So Int1 is now known.

I would like to take only 30 % of this integral and find the unknown upper limit (a2):

% Find the uper limit of the integral [0,a2], a2 is unkown

fun1=@(a2)quad(@ppval,0,a2,[],[],pp)-0.30*Int1

funq1=@(a2)fun1

a2=fzero(funq1(a2),[0,x(end)])

Assuming that now I would like to find a1 and b2:

How can I do it.

I highly appreciate your helps.

cheers

Adam