@Carl Love 

min the end of loop a have a new L

so I need to recount differential equation 

@Carl Love 

yes

but I need to recount it every time

while y(2)=0

if there is no such values 

I need to print l2-l1 which are the closest one 

@tomleslie Will this work for differential equations such as the boundary value problem?

@tomleslie I'll try 

thank you so much