Author Topic: C3 and C4 DOUBTS HERE!!! (Read 36192 times)

RoRo · « **Reply #75 on:** April 05, 2011, 02:18:36 pm »

Quote from: mdwael on April 05, 2011, 12:10:03 pm

Do we have to memorize the expansions of Sin(A+B), Cos(A+B), CosA CosB- SinA Sin B or they'll be given in the formula booklet?
Also does anyone know a helpful website to help me in chapters 6 and 7? (tirgnometry)

They'll be given to you in the formula booklet.
Check this site: http://www.trigonometry-help.net/

Arissa_04 · « **Reply #76 on:** April 05, 2011, 06:10:08 pm »

Hey guys, need help in a trig question.not sure which year it is is from.Here's how the question goes:

Using the expansion of cos(3x-x) and cos(3x+x) prove that:

1/2(cos2x - cos4x) = sin3x sinx

Its a 3 mark question so I'm pretty sure its not that complicated but I cant seem to get the answers.
Thanks in advance Smiley

mdwael · « **Reply #77 on:** April 06, 2011, 10:50:51 am »

Anyone got a link or could upload the formula booklet which is provided when you do the Maths Edexcel exam?

RoRo · « **Reply #78 on:** April 06, 2011, 05:12:12 pm »

Quote from: mdwael on April 06, 2011, 10:50:51 am

Anyone got a link or could upload the formula booklet which is provided when you do the Maths Edexcel exam?

I had asked the same question on Page 3, there you go with the link:
http://www.edexcel.com/migrationdocuments/GCE%20New%20GCE/N38210A-GCE-Mathematical-Formulae-Statistical-Tables.pdf

RoRo · « **Reply #79 on:** April 30, 2011, 09:33:50 am »

Can someone please explain to me how do you part b and c?

astarmathsandphysics · « **Reply #80 on:** April 30, 2011, 10:00:55 am »

Complete the square for the numerator to get (x+1/2)^2+3/4>=3/4

Aadeez || Zafar · « **Reply #81 on:** April 30, 2011, 10:08:06 am »

b)

let x²+x+1 be equal to y
y = x²+x+1
= x²+x+.25+.75
= (x+.5)²+.75

there fore (x+.5)² is a positive number and so .75 added to positive number gives positive number

and so

y is positive
therefore y>0
=x²+x+1>0

C)²+x+1 is positive and (x+2)² is positive so positve number divided by positive is positive and so f(x) is positive

so therefor f(x)>0

RoRo · « **Reply #82 on:** April 30, 2011, 10:21:48 am »

Quote from: Mr. MUST on April 30, 2011, 10:08:06 am

b)

let x²+x+1 be equal to y
y = x²+x+1
= x²+x+.25+.75
= (x+.5)²+.75

there fore (x+.5)² is a positive number and so .75 added to positive number gives positive number

and so

y is positive
therefore y>0
=x²+x+1>0

C)²+x+1 is positive and (x+2)² is positive so positve number divided by positive is positive and so f(x) is positive

so therefor f(x)>0

Okay, thank you very much!

Blizz_rb93 · « **Reply #83 on:** May 31, 2011, 12:01:44 pm »

f(x) = x + 3/x-1 - 12/x^2 + 2x -3 [x is an element of all eral number, x>1]

Show that f(x) = x^2 + 3x + 3 / x+3

in the book page 11 mixed exercise 1e q4

Thank you

thenewkid™ · « **Reply #84 on:** June 08, 2011, 11:15:14 pm »

anybody have any revision notes or pointers?

thenewkid™ · « **Reply #85 on:** June 08, 2011, 11:15:45 pm »

anybody have any revision notes or pointers?

deadlyelder · « **Reply #86 on:** June 10, 2011, 06:43:49 am »

Have attached the C3 Revision Sheet from http://www.r9paul.org/resources/a-level/ check the site for more notes on M1, M2, Physics, Computing and Religion Studies. They are quite handy notes.

Cheers

thenewkid™ · « **Reply #87 on:** June 11, 2011, 02:07:06 pm »

THANKS

studz · « **Reply #88 on:** June 12, 2011, 06:31:12 pm »

guys how are the last three chapters of c3 coming up for u all?
i am having alot of difficulty studying those last 3 chapters!

any tips on how to get those chapters in my head? :/
i did those 3 chapters from the book twice but i still cant get them in my head!! $:-\$

thenewkid™ · « **Reply #89 on:** June 13, 2011, 06:53:50 pm »

those chaps are plain nightmares, the only way out is practice $:-\$

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