Q16 (3 Viewers)

[Timske]

Step by Step solutions for B and C please!

post up the question i forgot it already lol

 

[cookeemonstah]

sud get about 90-92% raw mark, do you guys have any idea what that would align to

94? (95 if lucky and every1 else screws up)

 

[medicore]

wow, you guys are boss. I couldn't do 16 B and C LOL, A was good.

 

[mytstephen]

radians/degrees?=/

Hey
For question 16)b)iv)... about finding theta that gives the minimum area of the trapezium... I wrote 30 degrees instead of in radian form (pi/6)...

Do you think I'll loose marks for this?
I surprised myself by even getting that far... it'd suck if I don't get the mark for it=/

THANKS

 

[Kimyia]

Re: radians/degrees?=/

I'd say it depends on the marking critera, but it did say 0 < theta < pi/2 so I think they would have preferred radians :\
But then again, its still the same thing so I'm not sure.

 

[cookeemonstah]

Re: radians/degrees?=/

iono cant remember if question asked for radians. If it did then ... gg

cant remember if they gave out half marks or not.

 

[freeeeee]

dam was it pi/6, haha i got like 47degrees

 

[DefiningTheta]

I left my answer in degrees... do you think this will affect anything?

Yes, the question asked 0 < theta < pi/2. So radians, not degrees.

 

[usmas]

C(I) that was just probability: P=(1/n^k-1){k(n-1)/(n-k)x(n-2)/(n-k-1)x...(n-k)/(...)} then simplify
C(II) substitition of k+1 in I, then solve simultaneous
(III) look for discrimant
(iv)??

 

[Timske]

C(I) that was just probability: P=(1/n^k-1){k(n-1)/(n-k)x(n-2)/(n-k-1)x...(n-k)/(...)} then simplify
C(II) substitition of k+1 in I, then solve simultaneous
(III) look for discrimant
(iv)??

16C had 2 parts, wrong thread

 

[megaman64]

Re: radians/degrees?=/

did you have to prove this is a minimum by doing 2nd derivative because i just finished the question by writing pi/6

 

[eat_well]

For 16.c)ii)

Rearrange 4c=1+4r^2
c=1/4+r^2
r^2=c-1/4
r=(c-1/4)^2

If you take the square root of 1/4, you get 1/2
Since r>0 then c>1/2

I made silly mistakes everywhere else in the paper though and i didn't get 16.c)i)

 

[mytstephen]

Re: radians/degrees?=/

did you have to prove this is a minimum by doing 2nd derivative because i just finished the question by writing pi/6

Yeah I proved it was a minimum and everything... it's just that it's in degrees...

 

[DefiningTheta]

Re: radians/degrees?=/

The domain was between 0 < theta < pi/2

 

[Jashua_Long]

Re: radians/degrees?=/

you lose, they wanted it in term of pi

 

[DefiningTheta]

Also, unfortunately, the BOS doesn't give out 1/2 marks.

 

[nirukk]

How do you even start 16b ?

 

[RishBonjour]

Re: radians/degrees?=/

did you have to prove this is a minimum by doing 2nd derivative because i just finished the question by writing pi/6

yep, you always have to prove it :/

 

[gr_111]

This is for 16b)

gradient OT = tan theta, therefore gradient tp = -1/tan theta...

point T is (cos theta, sin theta) and use equation of a line formula

 

[nirukk]

This is for 16b)

gradient OT = tan theta, therefore gradient tp = -1/tan theta...

point T is (sin theta, cos theta) and use equation of a line formula

Point T is (cos theta, sin theta) or the other way around ?