@Mariusz Iwaniuk 

thank you, indeed a little correction

but with my maple version 13 it dose't work !

@Preben Alsholm 

Thank you for your help

@tomleslie 

i like your answer, because I can follow you.

I don't unterstand the philosophy of Maple , why Maple don't offer this function, some how, in my case I 

need it to obtain the frequency of the wave 

Thank you for your help

@panke 

I don't unterstand why so complicate to get answer for my simple quation? or you can't solve this problem ?

please let me know, so I look for alternativ solution .

Warning, cannot evaluate the solution further right of .50003810, event #1 triggered a halt
Warning, cannot evaluate the solution further right of 1.0000762, event #1 triggered a halt
Warning, cannot evaluate the solution further right of 1.5001143, event #1 triggered a halt
Warning, cannot evaluate the solution further right of 2.0001524, event #1 triggered a halt

I nned all the events points

Thank you

@mmcdara 

If you start my program you get this warning

Warning, cannot evaluate the solution further right of .50095360, event #1 triggered a halt
Warning, cannot evaluate the solution further right of 1.0019072, event #1 triggered a halt
Warning, cannot evaluate the solution further right of 1.5028608, event #1 triggered a halt
Warning, cannot evaluate the solution further right of 2.0038144, event #1 triggered a halt

how can I get the time t=.5,1.0,1.5,2 this was my quation

Thank you

@dharr 

this is my maple code

maple_event_test.mw

@acer 

Tank you for your rsponse and help

Tank you for your help

plotproc.mw

this don't word in dsolve ?

@acer 

how can I use this proc (RPM)  in dsolve([...].numeric...)?

@Carl Love 

this equation control a state event, if you know what it is? So it make sense!

@Carl Love 

f_i are Heaviside function of x3l, so I get  recrusive error

x31 is a function of f1 f2 and f3 , f1 i,f2, f3 are functions of x31 so you get algebraic loop. Maple error x31 is recursive 

@Kitonum 
Thank you, but I used I_w ... not I , I think Maple schuld recognized this ?

@acer 

Thank you for your help

@Joe Riel 

Thank you it work!!!