jinny1's Specialist Questions Thread :D

[xZero]

6. a.b = |a||b|cos(theta), if they are in the same direction, theta = 0, cos(theta) = 1, hence a.b=|a||b|

7. same thing, if they are in the opposite direction, theta = 180, cos(theta) = -1, hence a.b=-|a||b|

1. see how k is just a multiplier, we can put k into the bracket and it can belong to either a( ) or b( ) Hence k(a.b) = ka.b = a.kb

[jinny1]

Thanks ur awesome!, this is a screenshot of the rules btw

[jinny1]

Guys i'm baffled by this question. Q9.a)



Here's a the start of the textbook's worked solution. in which their final solution was 4.37 minutes or 4 minutes and 22 seconds.



I thought instead of following that method, i would try a different calculator only way.

So my basic equation was t=(1/k)ln(T+6)+C

and then i used my calculator to exactly find k and C (simultaneous equation) and then just put T=0 to find t.

my calc says 11.0507 minutes. So i'm wondering if you get a different answer when you use t=(1/k)ln(A(T+6)) , instead of what i used. Because i thought it shud be the same, i mean the textbook uses that method just so it is easier to do by hand.

Thanks

[b^3]

What values did you get for c and k?
where they and

I got the right answer, I'm thinking that maybe the use of capital T and t may have out you out on the calc

[b^3]

ok so the two equations you should be putting into the calc are


solving gives  and
T=0 means that we have
which gives

[jinny1]

Thank you mate, so it probly was a calculation error.

Sorry for the late reply, i thought i set up automatic email notification but i think that got reverted when the forum changed the design

[jinny1]

Guys i was wondering if it was possible to do Euler's method on the calculator (Ti-nspire classpad) or at least check if the answer is right..

Cheers

[pi]

Guys i was wondering if it was possible to do Euler's method on the calculator (Ti-nspire classpad) or at least check if the answer is right..

Cheers

Don't think there is an easy way. You can do some complicated method with tables, but it's not worth the time. Sorry

[yawho]

What is the point in using CAS to find approx solution by Euler's?

[Mao]

Guys i was wondering if it was possible to do Euler's method on the calculator (Ti-nspire classpad) or at least check if the answer is right..

Cheers

I wrote a program for the TI-89 which does precisely that. I'm not sure if the TI-nspire has similar programming capabilities (or if the programming language is still the same). I can post it if you want.

[jinny1]

Guys i was wondering if it was possible to do Euler's method on the calculator (Ti-nspire classpad) or at least check if the answer is right..

Cheers

I wrote a program for the TI-89 which does precisely that. I'm not sure if the TI-nspire has similar programming capabilities (or if the programming language is still the same). I can post it if you want.

Yes Please!!! I'm sure they work differently but i'll give it a go Thanks

What is the point in using CAS to find approx solution by Euler's?

So you can double check the answers, or just use the CAS when it is a MC question

[Mao]

Guys i was wondering if it was possible to do Euler's method on the calculator (Ti-nspire classpad) or at least check if the answer is right..

Cheers

I wrote a program for the TI-89 which does precisely that. I'm not sure if the TI-nspire has similar programming capabilities (or if the programming language is still the same). I can post it if you want.

Yes Please!!! I'm sure they work differently but i'll give it a go Thanks

Code: [Select]

:eulert()
:Prgm
:DelVar x,y,dx,dy,t,yp
:ClrIO
:Input “dy/dx”,yp
:Input “x initial”,x
:Input “y initial”,y
:Input “step size”,dx
:1→t
:Define list1={}
:Define list2={}
:Input “x final”,s
:(s‐x)/dx→s
:While t≤s
:Define list1[t]=x
:Define list2[t]=y
:yp*dx→dy
:x+dx→x
:y+dy→y
:t+1→t
:EndWhile
:Define list1[t]=x
:Define list2[t]=y
:Disp y
:Disp approx(y)
:DelVar t,x,y
:DelVar yp,dx,dy
:EndPrgm

Good luck getting it to work!

[jinny1]

  

[pi]

@Mao, I tried to input that with ti-nspire programming a few months ago (same as in your bound ref right?), it doesn't work. the nspire lacks in the programming department atm

[Lasercookie]

@Mao, I tried to input that with ti-nspire programming a few months ago (same as in your bound ref right?), it doesn't work. the nspire lacks in the programming department atm

At least the nspire has some form of Lua, that has to count for something right?

Moderator action: removed real name, sorry for the inconvenience