That's because differentiation is a function of higher education, which we already know you do not have. So, I understand why you would say that.
Did you pass? And judging by much of your post history, I bet you were far better at differentiation than integration.
<iframe width="640" height="360" src="http://www.youtube.com/embed/cNkp4QF3we8?feature=player_embedded" frameborder="0" allowfullscreen></iframe> In case you still wonder about 'Mum' c
Back when there was 24/7 media coverage of Princess Diana's funeral, the family (William/Harry) could be seen walking behind the hearse and on on the back of the hearse was a large handwritten sign "Mummy". I remember the irony of the word even knowing what it meant in "British" terms.....