In a recent 3u exam, my friend used a method that a tutor taught him that goes beyond the syllabus. In this test, he used definite integrals or something to skip the whole evaluating the constant part of the working out in projectile motion (I think).
Now it obviously works since he got all the answers right, but the teacher that marked it HATES tutors (she's a dumb b*tch who thinks tutors are useless etc.) and wrote 'I have never seen this method before. This is not a valid method, you must use what you have learnt in class.'
Because of this, my friend lost 3 marks (he used the method in 3 different questions, losing a mark for each time) costing him first place.
So my question is: is the teacher allowed to do that?
LOL.
Valid but not approved.
Definite integral method is really awesome, saves time but I don't want to be a fool and try something different to risk losing marks.
What the HECK is the definite integral method ?
Do you mean breaking it down such that you have
x acceleration = 0
y acceleration = 9.8
Then integrating from there and subbing in initial conditions ?
This is the indefinite integral method everyone is familiar with:
y" = - g
y' = ∫ - g dt
y' = - gt + C
When t = 0, y' = y'0
y' = - gt + y'0
There were limits in the integral sign.
I'm curious how that even works in the HSC.
I don't think we were even taught that in 1st year physics.
The indefinite integral method is best applied to solving differential equations via the separable method which is in MATH1231 (First year session 2) you remember?
So that person should lose marks anyway lolol sucked in.
I think what he means by the definite integral method version is:
[maths]\frac{\mathrm{dv_{y}} }{\mathrm{d} t} = -g[/maths]
[maths]dv_{y} = -g\; dt[/maths]
[maths]\int_{v_{y0}}^{v_{y}}dv_{y} = \int_{0}^{t}-g\; dt[/maths]
[maths]v_{y} - v_{y0} = -gt[/maths]
[maths]v_{y} = -gt + v_{y0}[/maths]
Which is pretty much the same solution as the indefinite integral method.
AND FUCK TUTORS this is why you don't use redundant methods offered by tutors.
