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1028
7
avatar+502 

Differentiate 

5x - 7 + 2x-1/2 + 3x-1

 Nov 25, 2017
 #1
avatar+33603 
+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!

.

 Nov 25, 2017
 #2
avatar+502 
+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
avatar+33603 
+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
avatar+502 
+2

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

Rauhan  Nov 25, 2017
 #5
avatar+33603 
+2

The answer sheet has the results as indicated by the red boxes below (you still need to add them together):

 

.

Alan  Nov 25, 2017
 #6
avatar+502 
+3

So the answer is 5 - x-3/2 - 3x-2

Rauhan  Nov 25, 2017
 #7
avatar+33603 
+3

Correct!

Alan  Nov 25, 2017

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