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Quotient rule?

Asked to differentiate this function:

Used quotient rule but I don't know why the answer I've got which is right is different to how the answer is given, don't know what method they have used?
The answer given is like this:

Then simplified to:

Please can someone explain to me how they have split it into two fractions and how it is simplified? I know it's really easy but my mind is just not working well right now. :colondollar:
Thanks! :biggrin:
Reply 1
Original post by xCBRx
Asked to differentiate this function:

Used quotient rule but I don't know why the answer I've got which is right is different to how the answer is given, don't know what method they have used?
The answer given is like this:

Then simplified to:

Please can someone explain to me how they have split it into two fractions and how it is simplified? I know it's really easy but my mind is just not working well right now. :colondollar:
Thanks! :biggrin:


they are using this law: (a + b)/c = a/c + b/c
And then they simplify which is why the "c" in the answer is different in both parts
(edited 13 years ago)
Reply 2
Original post by R3L4Y
they are using this law: (a + b)/c = a/c + b/c
And then they simplify which is why the "c" in the answer is different in both parts


Thanks! Now I understand the first part but I still don't get the final answer. :frown:
Reply 3
Original post by xCBRx
Thanks! Now I understand the first part but I still don't get the final answer. :frown:


hahha I kno...I was lookin at it just now..and I'm just as stuck as u atm. I know they put them back together and multiply out a part of it..but...still cant manipulate it round to give me that answer
(edited 13 years ago)
Reply 4
Original post by R3L4Y
hahha I kno...I was lookin at it just now..and I'm just as stuck as u atm. I know they put them back together and multiply out a part of it..but...still cant manipulate it round to give me that answer


got it..yeh..you just have to get common factor (1 +x^2)^5 and then factorize and multiply out "the" bracket and then you get 12x(1+x^2)^5*(1-x) as ur numerator
Reply 5
Original post by R3L4Y
hahha I kno...I was lookin at it just now..and I'm just as stuck as u atm. I know they put them back together and multiply out a part of it..but...still cant manipulate it round to give me that answer


Ah well, at least you helped me with the first part, I thought they used another method to differentiate that we hadn't learned and I was really confused.
Reply 6
Original post by R3L4Y
got it..yeh..you just have to get common factor (1 +x^2)^5 and then factorize and multiply out "the" bracket and then you get 12x(1+x^2)^5*(1-x) as ur numerator


OK thanks! I haven't fully worked that out but I understand what you mean. :biggrin:

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