Assignment 1

I'm having trouble with Question 7 of assignment 1.

I think all three options 1, 3, 4, are all correct...

Let me know if what you guys think.

Question 10 assignment 1

Are they asking is newtons method is guaranteed in genral or for f(x) stated at the top of Section B?

I find that newtons method converge with starting x = 0.5 at 0 and starting x = 1.5 at 1.2927 for f(x)
check this out

Give me more details and maybe I can share the benefit of my having already supped this one with you.

I don't have this semester's tut letters, so your question references are no help. Probably plain answers are in the plagiarism zone, but a discussion of the principles is clearly not.

Question 7


Question 10

OK the path to part of the answer may be to punch ln(-1) into an imaginary calculator, remember the result, and then imagine on which side of the circle you'd find 2.6 radians. In other words I think you should be getting an error in your second iteration.

Sorry, I forgot about Q10.

All the questions will relate to the f(x)'s given at the top of each section,
so your f(x) = e^-x - cos x.

I haven't looked at the main calc yet. I'll feed it all into Octave sometime, I think, and make a plot. (Although the right way here would probably be to draw a rough graph, so you can see what answers you ought to expect in a way that may become applicable in the exam).

Thanks a lot.

I took everything you said, and thought about it some more.

And it all makes more sence now.

Thanks
C

Glad to be of help - although the marking machine will decide whether that, it really was. I still have to make that rough graph etc.

A word of advice: You need to get onto Assignment 2's stuff as early as you can. The hill gets significantly steeper up ahead.

It's also a very good idea to do Assignment 3 (if they're still running that system where a genuine effort gives you full marks).

OK, I've now satisfied myself that the comments to question 7 could be helpful.

An addition to that (no longer relevant to you, ROtti, but just to the question) would be that the issue of where those roots are, and whether your method converges toward them from such and such an initial value are two separate things.

As for Newton's method, doesn't one have to start out reasonably close to the root to get there?

I'm not sure but I wrote a function in Matlab that does Mullers Method and the answers I get for 14 and 15 are close but not identical.
14: a=-0.25; b=-2; c=0.0625; root=1.5311
15: a=32; b=46; c=13; root=2.6134

Number 13 is way out and isn't close to any of the answers. I hope I don't have a bug in my program.

hehehehehehehe

Clever, but they want you to use Mullers method. I can't get those numbers to come through exactly with Mullers - thats the bigger concern.

I'm looking at assignment 2 and its a mountain of work!

Out of curiosity, how are we supposed to solve some of this staff in the exam without the use of computers. It could take forever! I'm considering buying a graphing calculator....

Scratch that. The past papers say non programmable calculators only!!

Start practicing your calculator-typing now. Even if you use CAS etc to do checks, be sure you can do it by hand, and do a rerun just to drill yourself, so you build up some speed.

Mind you with this last exam I had quite a lot of time to punch the calculator, on account of my hitting such a complete and utter blank with some of the questions that I gained a lot of time for the stuff I half-understood.

... No, actually that's wrong. I'd say my understanding was OK (not brillig, but at least OK). You need more than just understanding. You need to carry that understanding forward to the point where you have skill.

Here's an idea: Even as you struggle along with the glitches in Assignment 1, do question 1 of Assignment 2. Nothing more. Don't make the goal too big. Just question 1. Get a bit ahead of the game. And then a bit more. You need to do this, because they will do the dastardly trick of asking you to think in the exam!

I see this assignment was cancelled? The model answer is still not published though. Has anyone called to request it?

Can someone send me all the tutorial letters including the answers please. My email add is: moha_4m@hotmail.com. Have a supplementary exams and i cant access them anymore on my.unisa