请教一个matlab双重积分的问题

try to write the integrand as f(y)*(a(x)<y)*(b(x)>y) to see if it works.

多谢！
总是蹦出来matrix dimension must agree之类的错误
我最后还是用循环来叠加计算的。。。计算量还行，可以忍受

In case of such errors, try to add a "." in front of all operators, that is, use , ./, .^ and so on, instead of *, /, ^. It is a common error in dealing with integration. To reduce complexity, Matlab intend to collect a bunch of samples and calculate them together--that will cause this error.
By the way, dblquad is not good in terms of both accurary and speed.