@Kitonum can you more explain to me  please ?

@Carl Love but it doesn't work also if i choose 1/sqrt(2*x+1); its gives to me the same thing, can you explain to me please !

@Kitonum thank you for your response, but if i clic in the palette i is called imaginaryunit and also I interface(imaginaryunist) what is the diff between them ?

@tomleslie thank you very much for you response, i want to more understand this commands , can you advice me or give more details ?

@vv i can't calculate it with maple !!

@vv thank you for your answer, can you help me  to do it manually ?

@tomleslie thank you for your answer, it was very useful for me , but why in the second case maple did not order the elements of the set E ?

@Kitonum thank Mr.Kitnoum, but in maple v , it gives me error why ?

thank you Mr.@Kitonum for your clarification but for example if i want to calculate sin(0.2) maple gives me 0.1986693308, maple does not know the explicit value of sin (0.2) if i want to evaluate it i have to use evalf that's the thing i have not understood yet, it gives me a value how that ?

thank you Mr,@acer for your help, what does this mean, why mapleV R4 give this result, can  you help me to understand this, i'm realy confused ?

thank you very much Mr,@acer ,it was very helpful for me, 

thank you mr @Kitonum for your help, can you provide me with a book to understantd how maple works ?

@Preben Alsholm  for academic use 

@Kitonum thank you  you're right i was wrong thank you very much.

@John Fredsted yes, i'm searching to simplify the expressions to get all the equilibrium points of this system.