Author Topic: maths doubts  (Read 3603 times)

Offline cooldude

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maths doubts
« on: October 30, 2009, 07:01:13 am »

and also one sequence i gotta doubt in this sequence-
what will be the nth term in the following sequence-
(start with n=1)


13,14,18,27,43,68

« Last Edit: November 09, 2009, 12:29:39 pm by cooldude »

Offline astarmathsandphysics

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Re: maths doubts
« Reply #1 on: October 30, 2009, 07:15:28 am »
13 14 18 27 43 68
    1   4   9  16  25
u(n+1)=u(n)+n^2

For the others, do you want the solution to every one?

Offline astarmathsandphysics

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Re: maths doubts
« Reply #2 on: October 30, 2009, 07:17:33 am »
Usuuallly if they want you to solve a quadratic equation they ive you want of the roots.

Offline astarmathsandphysics

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Re: maths doubts
« Reply #3 on: October 30, 2009, 02:25:52 pm »
The only way you can do them systematically is using iteration/trial and improvement (really long method)/ bisection (also really long) or the Newton Raphson Method. There are exact methods but these are not part of IGCSE or even A level maths. Which method have you been taught to use?

Offline astarmathsandphysics

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Re: maths doubts
« Reply #4 on: October 30, 2009, 04:03:38 pm »
I will have to do it tomorrow. Something urget came up and I will be occupied for the rest of the day. There will be an announcemt tomorrow.

Offline astarmathsandphysics

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Re: maths doubts
« Reply #5 on: October 31, 2009, 08:09:12 am »
I have been thinking seriously about this since yesterday. I don't seriously think they can expect you to find all three roots of a cubic polynomial using the Newton Raphson method. You dont even know how many roots there are. The very first thing you would have to do would be to sketch the curve and see if you can find interval in which each root lies. Can you scan in the page with the question? I think there is something missing.

Offline Ghost Of Highbury

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Re: maths doubts
« Reply #6 on: October 31, 2009, 09:42:15 am »
if u use Fx-991Ms

do this,..


On-->3 times "mode"--> "1" (Eqn) --> press the "right arrow" --> "3" --> type th co-efficient of x3 nd press "=" -->

type th co-efficient of x2 nd press "=" --> type the co-efficient of x nd press "=" --> type the value of "d" i.e co-efficient of x0 and press "=".

U'll get an answer..press "=" 2 more times to find the other values

e.g -> a cubic equation --> ax3 + bx2 + cx + d
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Offline slvri

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Re: maths doubts
« Reply #7 on: October 31, 2009, 09:43:35 am »
coooooool.....i didnt know that........
so wassup adi? hw r ur papers going?
i hate A level...........

Offline Ghost Of Highbury

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Re: maths doubts
« Reply #8 on: October 31, 2009, 09:44:33 am »
coooooool.....i didnt know that........
so wassup adi? hw r ur papers going?

hey..ssup..actually u can solve matrices and simultaneous equations too in Fx-991 MS.

and yea..my papers are going good..2morrow again a holiday followed by english paper 3!
divine intervention!

Offline @d!_†oX!©

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Re: maths doubts
« Reply #9 on: October 31, 2009, 09:45:10 am »
if u use Fx-991Ms

do this,..


On-->3 times "mode"--> "1" (Eqn) --> press the "right arrow" --> "3" --> type th co-efficient of x3 nd press "=" -->

type th co-efficient of x2 nd press "=" --> type the co-efficient of x nd press "=" --> type the value of "d" i.e co-efficient of x0 and press "=".

U'll get an answer..press "=" 2 more times to find the other values

e.g -> a cubic equation --> ax3 + bx2 + cx + d
dude!!!
fx-991 MS isn't allowed!!!!
AAL IZZ WELL!!! ;)

Offline Ghost Of Highbury

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Re: maths doubts
« Reply #10 on: October 31, 2009, 09:45:56 am »
dude!!!
fx-991 MS isn't allowed!!!!
ofcourse it is allowed..all of us used it in paper 2 maths..which calculator do u use?
divine intervention!

Offline Ghost Of Highbury

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Re: maths doubts
« Reply #11 on: October 31, 2009, 09:47:52 am »
ofcourse it is allowed..all of us used it in paper 2 maths..which calculator do u use?

one of my friends used Fx-991 ES..which is better..

u can directly get the table by simply typing an expression..
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Offline @d!_†oX!©

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Re: maths doubts
« Reply #12 on: October 31, 2009, 09:48:59 am »
damn man!!!!
I know about ES too....i used that inititally
but acc. to our school it's not allowed....
we've gottause that s*cky 82 MS
THIS IS BAD!!!!!!!!!!!!
AAL IZZ WELL!!! ;)

Offline astarmathsandphysics

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Re: maths doubts
« Reply #13 on: October 31, 2009, 09:49:19 am »
yes that 991ms is allowed. Brilliant calc. I have one and always recommend it.

Offline Ghost Of Highbury

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Re: maths doubts
« Reply #14 on: October 31, 2009, 09:50:51 am »
damn man!!!!
I know about ES too....i used that inititally
but acc. to our school it's not allowed....
we've gottause that s*cky 82 MS
THIS IS BAD!!!!!!!!!!!!

hahaha..amazing!!!...wow!!..i mean that fx-81 MS..is the best calci i have ever seen.lol!!..

go buy a new one rite noww!!
divine intervention!