Q7 (1 Viewer)

[Riviet]

Discuss.

My thoughts:
Attempted everything except for (a) (ii).
I got the induction, which I'm still ecstatic about.

 

[zeek]

me too! omfg the INDUCTION KILLED ME...
i did like 2 pages and then FINALLY i got it after reading the top bit lol

i did the reduction question that was ok jst took time

part a was hard, i found the derivatives and said that their multiples must equal -1 but it never did i only ended up with some shitty trig equation... oh well i might get some marks for that.

 

[Riviet]

In (a) (i), you had to realise that the point of intersection has a common y-coordinate, so cos@=tan@. Differentiate and find your gradients, use cos@=tan@ to show the gradients multiply to give -1. Easy 3 marks in my opinion.

 

[Bricnic]

In (a) (i), you had to realise that the point of intersection has a common y-coordinate, so cos@=tan@. Differentiate and find your gradients, use cos@=tan@ to show the gradients multiply to give -1. Easy 3 marks in my opinion.

I had that idea in mind, couldn't work it out for some reason. Sucks.

 

[NDSUTHERLAND]

DAMN...Didn't think bout that!!!!! spent like 5-10mins trying to do trig had sin^2@ running round all over the place. grrrrrrrrrrrrrr IDIOT *bangs head in frustration*

 

[gamecw]

Q7

(i)prbly made a mistake during calculation coz my ending didnt turn out to be right
(ii) got that with a negative sign??? must be mistake during calculation too
(2 marks)

b. yep that was easy (5 marks)

c(i).got 1 mark for proving n=1
(ii) lol yep got that out wasnt it -2? cant remember
(2marks)

so i got 9/15 60% wasnt too bad

 

[pLuvia]

Q7 was alright, just didn't get part a

 

[CheekyPunk]

far out, 7a is easy once you know how to do it xD

ahhh, i stuffed 7, was running out of time and didnt really do any of it. Probably could have done at least the reduction formula if i had the time. but i didnt.

so instead, i did bii and cii, the hences haha, a few marks is better than none.

 

[Lizcat]

i could do 7a and b, how do u do the induction??!

 

[Riviet]

Part of the induction was to divide top and bottom by 3, then notice that

(alpha)^k/3 = 1 - (-1/3)^k/3
= 1 + (-1)^k+1.(1/3)^k+1
= 1 + (-1/3)^k+1
= 1 + (alpha)^k+1

Similarly on the denominator 1 + (-1/3)^k/3 = 1 - (alpha)^k+1

 

[Lizcat]

nah nah.. it doesnt matter.. NO MORE 4U maths!! woo hoo!. hehe