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# C3 Exam Question confusion ???? watch

1. Hey guys, I’m hoping one of you guys could ease my doubts today, How would you go about answering the following question ? ;

7) The curve C has equation
y= ln(x^2 +1)/x^2 + 1

a) find dy/dx as a single fraction

b) hence find the exact coordinates of the stationary points of C.

Thank you so much in advance btw )))))
2. did this in the exam today, got (0,0) and ((e-1)^1/2,1/e)
3. (Original post by martin12345673)
did this in the exam today, got (0,0) and ((e-1)^1/2,1/e)
Do you mind showing the working out ?
4. c3 part a
Attached Images

5. (Original post by martin12345673)
did this in the exam today, got (0,0) and ((e-1)^1/2,1/e)
U missed the solution -(e-1)^1/2
6. part b
Attached Images

7. (Original post by Somebody1234)
U missed the solution -(e-1)^1/2
thought so, not quite sure though, thanks for lettting me know. what do you guys think about the grade boundaries? harder or easier than last year?
8. Similar to last year, 65-67 for a*, its the only boundary i look at coz i need it for my firm and insurance so idk about others soz
9. (Original post by martin12345673)
part b
yep thats but only thing i would say is remember when u sqr root u get a negative solution too so in fact u have 2 stationary points
10. (Original post by Anonymouspsych)
yep thats but only thing i would say is remember when u sqr root u get a negative solution too so in fact u have 2 stationary points
Yeah I made that mistake Hopefully it's only 1 mark gone though
11. (Original post by Anonymouspsych)
yep thats but only thing i would say is remember when u sqr root u get a negative solution too so in fact u have 2 stationary points
3 in total inc (0,0) (sorry if u were talking more generalised)
12. (Original post by Somebody1234)
3 in total inc (0,0) (sorry if u were talking more generalised)
ah yes i was only talking about the sqr rooted x value xD but yes u have another one with x=0
13. What do u guys think u got lookin at unofficial ms
14. im retaking, already have 92 ums in c4 from last year, i think i may have scraped 90 in this c3 but cant be sure so im going to have to destroy c4. THIS IS EDEXCEEEEEEEEEELL!
15. for the last question, did you have to leave the theta values in exact form?
16. (Original post by martin12345673)
for the last question, did you have to leave the theta values in exact form?
If a question doesn't say "give the answer in exact form", then you generally aren't required to. However, the question is split into parts, and the answer from one part is used in the next part, you should use the exact value, so that your working in the next part is accurate.

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