passing value(Post) to Mail function

please help me,im passing an email address from 1 page via a form and trying to
Mail it on the second page.

This works:-
[COLOR=Red]mail(“[email protected]“,”registration”, “welcome to
hello”,”From:”.$_POST[’email1′]);[/COLOR]

but i want the mail to be sent with email1 from the form.
ive tried these:-
[COLOR=Navy]$a=$_POST[’email1′];
mail(‘$a’,”registration”, “welcome to
hello”,”From:”.$_POST[’email1′]);

$a=$_POST[’email1′];
mail($a,”registration”, “welcome to
hello”,”From:”.$_POST[’email1′]);

mail(‘$_POST[’email1′]’,”registration”, “welcome to
hello”,”From:”.$_POST[’email1′]);
[/COLOR]
but they all return errors
hope ive been clear enough
thank you

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