haha i prolly got buttraped by the accelerated students too
question 10 1 markers were all good, i swear
if i didint panic within the last half n hour i would of got the rest lol =\
nice 10 minof scribbiling occurred resulting in inccorrect answers from the start due to wrong values.....anyway
for 9
c
i
looking at the cone, generic formula is 1/3 pi r^2.
in this instance , height of the cone ix h, we just need to eliminate r^2 as the variable to get x
looking at that nifty triangle,
you have sides
(x-a), r and hypnotenuse a
so, r^2 = a^2 - (x-a)^2,
when you get that pop that baby back into the generic formula
ii) differentiating it you should get something
then its like 4pi/3 on a or wahever, someone else posted an answer before; you need to have exact values to do the proving part easy.
prove its max by subbing into second derivative
which must always be negative, because side a is never negative
and on another note yep i got 800 L for that bit of question 9
surprisingly i thought q9 was pretty sweet but q10 lol, panicked on the rhombus question then panicked with 10
so retarted.