#1**+3 **

"*Differentiate 5x - 7 + 2x ^{-1/2 }+ 3x^{-1}*"

\(\frac{d}{dx}5x=5\\\frac{d}{dx}7=0\\\frac{d}{dx}2x^{-1/2}\rightarrow (-1/2)2x^{-1/2-1}\rightarrow -x^{-3/2}\\ \frac{d}{dx}3x^{-1}\rightarrow (-1)3x^{-1-1}\rightarrow -3x^{-2}\\\)

I'll leave you to add these together!

.

Alan
Nov 25, 2017

#2**+2 **

I am confused at what the answer sheet says

http://egyptigstudentroom.com/pastpapers/edexcel/alevel/gce/Math/Jan%202008/ms//8371_9374_GCE_Mathematics_msc_20080306_UA019869.pdf go to page number 9

Rauhan
Nov 25, 2017

#3**+2 **

I’m not surprised - it is the muddiest explanation I’ve ever come across!

Do you understand the derivatives in my previous reply, or do you need more explanation?

Alan
Nov 25, 2017

#4**+2 **

I understood how u did but i cant confirm ur answer with the answer of the answer sheet

Rauhan
Nov 25, 2017