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VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Specialist Mathematics => Topic started by: andrewloppol on October 22, 2010, 05:48:16 pm

Title: .
Post by: andrewloppol on October 22, 2010, 05:48:16 pm
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Title: Re: Some answerless problems from Hef 10 Ex2 MC
Post by: superflya on October 22, 2010, 06:09:08 pm
first question:

rewrite it as sin^2(x)cos(x)(1-sin^2(x))
then use the u substitution of sin(x), change ur terminals to 1 and 0. tidy it up and u should get C

second question:
id use the calc, cancel out the obvious options. dotP should equal 0 and the magnitude is 3. which is B.

third question:

so the inital momentum is 20. ur also given the final momentum of 80. p=mv, 80=20m so ur mass is 4kg. use that mass to calculate the initial velocity using 20=4u, u=5. so uve got both initial and final velocities and the the time, its all a matter of subbing into a constant acceleration formula, which in this case would          x=1/2(u+v)t
this gives 125, so option D
Title: Re: Some answerless problems from Hef 10 Ex2 MC
Post by: 98.40_for_sure on October 22, 2010, 06:15:36 pm
I remember this exam, it was nice :D
see attachments?
Title: Re: Some answerless problems from Hef 10 Ex2 MC
Post by: 98.40_for_sure on October 27, 2010, 11:46:01 am
The period is pi, thus cross out E.
At x=0, dy/dx=0, thus cross out B and D.
At x=pi/4, dy/dx~1, thus cross out A.
Leaves answer C
Title: Re: Some answerless problems from Hef 10 Ex2 MC
Post by: 98.40_for_sure on October 27, 2010, 12:41:41 pm
The period is pi, thus cross out E.
At x=0, dy/dx=0, thus cross out B and D.
At x=pi/4, dy/dx~1, thus cross out A.
Leaves answer C

is the graph the derivative?? i dont get it :S

All slope fields are graphs of GRADIENTS of individual points, not the derivative graph per se.
Title: Re: Some answerless problems from Hef 10 Ex2 MC
Post by: googoo on October 27, 2010, 01:30:20 pm
y=-cos(2x)+c, dy/dx=sin(2x)
Title: Re: Some answerless problems from Hef 10 Ex2 MC
Post by: m@tty on October 27, 2010, 01:49:35 pm
If you connect the lines you get the original graph, not the derivative.

So you can either recognise the graph, then differentiate it.

Or sub points into the options, to eliminate some, as 99.95 did.

EDIT: Points for the DERIVATIVE, ie. dy/dx and x. Just clarifying, though I hope you realised that yourself.
Title: Re: Some answerless problems from Hef 10 Ex2 MC
Post by: googoo on October 27, 2010, 02:28:22 pm
'irregular' slope field