IGCSE/GCSE/O & A Level/IB/University Student Forum

Qualification => Subject Doubts => GCE AS & A2 Level => Math => Topic started by: nid404 on February 01, 2010, 02:19:06 am

Title: Radians
Post by: nid404 on February 01, 2010, 02:19:06 am

Check the doc below. Please help me with the question
Thanks

Title: Re: Radians
Post by: Saladin on February 01, 2010, 08:02:05 am

this is quite hard. I'll do it after say 3 hrs.

Title: Re: Radians
Post by: nid404 on February 01, 2010, 08:40:47 am

Quote from: The Dude 321 on February 01, 2010, 08:02:05 am

this is quite hard. I'll do it after say 3 hrs.

No prob....I actually managed to get the right ans for the first bit....but I did it some vague way which i think is incorrect...If i don't show my method, I will get a big zero...
So take your time....jst gimme the steps if u get the ans. Thanks :)

Title: Re: Radians
Post by: Saladin on February 01, 2010, 09:43:55 am

how did u get the first answer, it doesn't make any sense, can u send me the paper, or have you missed out and information?

Title: Re: Radians
Post by: Saladin on February 01, 2010, 12:37:08 pm

this has to be a cambridge question, because I cant do it with the knowledge that I have abt radians.

Title: Re: Radians...astar help!!
Post by: nid404 on February 01, 2010, 01:45:08 pm

Yup it's CIE.....I think astar will be able to help
Thanks anyway

Title: Re: Radians
Post by: astarmathsandphysics on February 01, 2010, 01:45:46 pm

I am here lemme read the q

Title: Re: Radians
Post by: astarmathsandphysics on February 01, 2010, 01:57:05 pm

here

Title: Re: Radians
Post by: nid404 on February 01, 2010, 02:23:52 pm

Thanks a ton!

& m sorry im not able to help much and be as active cuz my mocks r comin up...I've wasted too much time...I have to study srsly now

Title: Re: Radians
Post by: Saladin on February 01, 2010, 02:31:45 pm

hey, i did it like that but i did not know i i got it wrong.

Title: Re: Radians
Post by: nid404 on February 01, 2010, 02:33:41 pm

Quote from: The Dude 321 on February 01, 2010, 02:31:45 pm

hey, i did it like that but i did not know i i got it wrong.

me too :(

Title: Re: Radians
Post by: nid404 on February 01, 2010, 02:35:08 pm

and 1 more
3x-4sin x=0

value of x within 0.1 rads...by tabulating values of 3x-4sinx and looking for a sign change, or otherwise

I feel stupid >:( :'(

Please help

Title: Re: Radians
Post by: Alpha on February 01, 2010, 02:40:04 pm

Quote from: nid404 on February 01, 2010, 02:35:08 pm

and 1 more
3x-4sin x=0

value of x within 0.1 rads...by tabulating values of 3x-4sinx and looking for a sign change, or otherwise

I feel stupid >:( :'(

Please help

Divide throughout by sin x.

3 cosec x = 4

Then, you can continue...?

Title: Re: Radians
Post by: nid404 on February 01, 2010, 02:43:38 pm

 ???

Please continue....cuz I don't knw how to find cosec inverse..... :-[

Title: Re: Radians
Post by: Alpha on February 01, 2010, 02:45:57 pm

Ah no....


3x cosec x....

Title: Re: Radians
Post by: Alpha on February 01, 2010, 02:49:04 pm

I'm not sure now... Will have to check...  :-\

By tomorrow I give you..? Hopefully... Have to go now...

Title: Re: Radians
Post by: astarmathsandphysics on February 01, 2010, 02:54:56 pm

Will have to do this when I get home.

Title: Re: Radians
Post by: Alpha on February 01, 2010, 02:56:42 pm

By graphical method..? can try

Title: Re: Radians
Post by: nid404 on February 01, 2010, 03:04:02 pm

Quote from: Cleo~patra on February 01, 2010, 02:56:42 pm

By graphical method..? can try

Graphical? I don't think it should be required...the question doesn't ask for it to be done graphically

Title: Re: Radians
Post by: astarmathsandphysics on February 01, 2010, 03:38:27 pm

Sign change method is best. When I get home

Title: Re: Radians
Post by: Alpha on February 01, 2010, 04:28:08 pm

3x= 4 sin x.

You can draw y = 3x and y= 4 sin x.

In case don't find any other way, you can try it.


Sign change method...?

Title: Re: Radians
Post by: astarmathsandphysics on February 01, 2010, 10:09:40 pm

x            3x-sinx
1      -0.37
1.05      -0.32
1.1      -0.26
1.15      -0.2
1.2      -0.13
1.25      -0.05
1.3      0.05
1.35      0.15
1.4      0.26
1.45      0.38
1.5      0.51
1.55      0.65
sign change between x=1.2 and 1,43 rads x=1.25 is too small sox=1.3 to 1 dp

Title: Re: Radians
Post by: nid404 on February 02, 2010, 10:38:02 am

Thanks :)

but could you also show it the other way(tabulation)...it would help me in the future

Title: Re: Radians
Post by: astarmathsandphysics on February 02, 2010, 10:41:14 am

That is the tabulation method