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

Qualification => Subject Doubts => GCE AS & A2 Level => Math => Topic started by: I'm a mistake - legalize abortion! on May 11, 2010, 12:43:17 pm

Title: P1 maths question
Post by: I'm a mistake - legalize abortion! on May 11, 2010, 12:43:17 pm: hello can anyone solve q no.4 from M/J 2009 pastpaper ?
it is a graph question

The diagram shows the graph of y = a sin(bx) + c for 0 ? x ? 2p.
(i) Find the values of a, b and c. [3]
(ii) Find the smallest value of x in the interval 0 ? x ? 2p for which y = 0
Title: Re: P1 maths question
Post by: nid404 on May 11, 2010, 12:46:07 pm: I've answered this before...hold on...ill get you the link
Title: Re: P1 maths question
Post by: nid404 on May 11, 2010, 12:49:18 pm: https://studentforums.biz/index.php/topic,7487.0.html

here you go :)
Title: Re: P1 maths question
Post by: I'm a mistake - legalize abortion! on May 11, 2010, 01:10:04 pm: thanks man you are the best ;D
Title: Re: P1 maths question
Post by: nid404 on May 11, 2010, 01:12:41 pm: You're welcome :) :P
Title: Re: P1 maths question
Post by: Saladin on May 11, 2010, 01:25:16 pm: Quote from: lord kratos on May 11, 2010, 01:10:04 pm
thanks man you are the best ;D

its a she! LOL
Title: Re: P1 maths question
Post by: I'm a mistake - legalize abortion! on May 11, 2010, 05:40:35 pm: oops!! i am sorry nid. :-[
I didn't see the sign
Title: Re: P1 maths question
Post by: nid404 on May 11, 2010, 05:45:04 pm: lol ...it's k :D
Title: Re: P1 maths question
Post by: AN10 on May 11, 2010, 07:08:58 pm: hey i have one confusion....when the question says that roots are REAL then is disriminant greater than or equal to 0,,,,,,OR only greater than 0,,,,,i hope u get what i mean.
Title: Re: P1 maths question
Post by: nid404 on May 11, 2010, 07:10:41 pm: real roots >0
repeated root=0
no roots <0
Title: Re: P1 maths question
Post by: ifraha18 on May 11, 2010, 07:30:16 pm: the function f is such that f(x) = (3x + 2)3 ? 5 for x ? 0.
ii) Obtain an expression for f?1(x) and state the domain of f?1.
..????
Title: Re: P1 maths question
Post by: nid404 on May 11, 2010, 07:31:16 pm: what is the ? in ur question
Title: Re: P1 maths question
Post by: ifraha18 on May 11, 2010, 07:32:29 pm: The function f is such that f(x) = (3x + 2)3 ? 5 for x ? 0.

wht is finverse of x.?n its rannge..june 2008 ppr 1 q6.
Title: Re: P1 maths question
Post by: ifraha18 on May 11, 2010, 07:35:46 pm: (3x+2)^3_5 for X>0

wht is finverse.?n its range.?
Title: Re: P1 maths question
Post by: nid404 on May 11, 2010, 07:38:46 pm: ohk..

here

y= $(3x+2)^3 -5$
to get inverse you make x the subject
$y+5=(3x+2)^3$
$3\sqrt(y+5)=(3x+2)$
$3\sqrt(y+5)-2= x$
-------------
$3$
$f^(-1)(x)=3\sqrt(x+5)-2$
-------------
$3$

now range of f(x)= domain of f^-1(x)
range of f(x) can be as the domain for it is given as x>=0
sub 0 in f(x) y>=3

this is the domain of the inverse function
D of f^-1(x) x>=3
Title: Re: P1 maths question
Post by: ifraha18 on May 11, 2010, 07:39:37 pm: Thanks..:)
Title: Re: P1 maths question
Post by: nid404 on May 11, 2010, 07:42:28 pm: just pray for me :)

ur welcome