Kilbaha 2010 Impossible Question

[Ovalteenies]

so i got up to this stage on the very last question, and my calculator just won't cooperate... no solution  
maybe it's something to do with my classpad, but even wolfram alpha won't solve it
correct answer is apparently 14.76

anyone got any suggestions/calculator fixes?

[ghadz7]

Instead of using V use another letter such as u. It works using ti-nspire CAS, which calculator do you have?

[Ovalteenies]

yea that's not the problem i used t

i have the classpad 330

[year12]

Yeah, I did this paper as well, and I just looked at the solutions and trusted that my cas would solve this for me.
So I didn't even check if i could do it on my calculator until I saw this thread!
And I have classpad 330 - it does not work on mine either. It spits out 'no solution'.
Hmmm,, finding a terminal from some methods questions worked.... e.g. probability finding median questions.
Maybe it can only solve easy ones!

Anyways, good luck for the next exam

[kyzoo]

I did this just last night, I didn't find anything wrong with the paper or my calculator =/

I put the same equation (using "x" instead of "V") and it comes up with "x = 14.7597 or x = 242.351"

[azn_dj]

Put the equation into my calculator 3 minutes ago.
My calculator is still thinking
...

EDIT: Yep. now its done.
Comes up as 14.759 or 242.32, I am assuming there is a domain restriction in the question.

I reckon the classpad issue may be because there are pre-defined variables? tried this? swap t for x and v for y?

[jasoN-]

doesn't work for me.. tried using different variables, even abc constants
eg.
continuously getting no solutions; fuck the CAS is shit.

[kyzoo]

Specify the domain to 0<V<20? I had the same kind of problem with VCAA 2009 Exam 2

http://vcenotes.com/forum/index.php/topic,31611.0.html

[jasoN-]

still not working, changed the domain to [0,20]
anyone using the classpad successfully solving this?
if so please type up exactly what you typed in the calc, ta

[chansthename]

Hmm, that's quite odd,

well here's what worked for me (and also what didn't)

[jasoN-]

what does it say after ',y,0 ...' and did  you change the variables into 'abc' constants?

[JinXi]

This works everytime, Integrate the equation using the integrand on your calculator, change you t's into x, then let y = the equation generated. Graph it, then solve for x at y=20.

[jasoN-]

cool, just found this out:
Go to Menu -> NumSolve
Type in the intergral: -> EXE
let y = any number (don't know what this is for), alternatively leave it blank (i guess this is the variable we're looking for)
Lower = 0
Upper = infinity (ie. the domain)

I GOT THE ANSWER =D, so happy now

[JinXi]

cool, just found this out:
Go to Menu -> NumSolve
Type in the intergral: -> EXE
let y = any number (don't know what this is for), alternatively leave it blank (i guess this is the variable we're looking for)
Lower = 0
Upper = infinity (ie. the domain)

I GOT THE ANSWER =D, so happy now

Nice find ^^ completely forgotten that we can use NumSolve for other thing, I have mine on the Quadratic formula so I dont have to waste time typing it in.....


The part where y =
It's only of re-valence when you have 2 or more unknowns, then you sub a value in for one and ask it to solve for the other unknown, given one.

Since there's only one unknown in this equation, selecting y would give the right answer ^^

[Ovalteenies]

wow thanks never knew about numsolve