i was thinking about the same...

the meaning is completely different!

does anyone know?

"Mutlu olmazsýn lazým" is absolutely incorrect.

"Mutlu olman lazým" = "You should be happy"

"Mutlu olman gerek" = "Mutlu olman lazým"

"Mutlu olmalýsýn" = "You must be happy" or "You should be happy"

"Mutlu olsan gerek" = "You must be happy"

Örnekler / Examples:

Gözün aydýn, deden Osmaniye´den döndü. Çok mutlu olsan gerek.

Congratulations, your grandfather is back from Osmaniye. You must be so happy.

Burada televizyon olmadýðý için niye bu kadar üzülüyorsun ki? Bence mutlu olmasýn. Kitap okumak için daha fazla zamanýn olacak.

Why are you so upset over not having a television here? I think you should be happy. You´ll have more time to read books.

Awesome, thank you for the explanation!

 Thanks for correction fuki.

I want to ask you something:

so

Negative for :

Ben is -mam/mem

Sen is -man/men or mazsýn/mezsin?

this one i dont understand... can you explain this for me?

is it a noun clause? like olma = being, and sýn = you are?

for me it looks like a verbstem+negative+2ndperson suffix.....

And I need someone to explain for me the negative for Sen(you)

do you mean for simple present?

that´s mezsin

gelmezsin = you don´t come

i think you are confused with olman = your being (a noun + a possesive).

in english this kind of noun is called gerund. its confussing because its the same as a negative command in turkish

gelme = (the) coming

gelme = dont come

 Yes, This one I wrote before:

Negative for :

Ben is -mam/mem

Sen is -man/men or mazsýn/mezsin? I am not sure please if someone know it, explain it for me

but for what kind of sentence?

simple present (negative)

ben: mam/mem

sen: mazsýn/mezsin

gerund

benim: mam/mem

senin: man/men

The gerund.. Thanks izah.. It was the thing I did a big problem with...... I mixed up -Mazsýn with -Man..Crazy me