Need help in C2

[gelato]

Hey guys, I have a question. How do you solve number 9 in C2 Jan 2012? For the first part, I got x=15 then I'm just stuck there and for part 2, I am totally lost. Help please

 

[gelato]

http://www.mathspapers.co.uk/edexcel.html
This is the link I use for past papers, btw. You have to download them though. It's Core 2, Jan 2012.

 

[iblue]

that question is too 'painful' for me to solve!!! any1 knws how 2 solve it?

 

[gelato]

Yeah...anyone?

 

[U stalking ME]

Hey guys, I have a question. How do you solve number 9 in C2 Jan 2012? For the first part, I got x=15 then I'm just stuck there and for part 2, I am totally lost. Help please

ok see the graph for sin intersects at three places on x axis that is sin is zero at 0, 180 and 360 or in radians at 0, π and 2π
so coordinates for points P ,Q and R are
P ( π/10 , o) -------> (π/10) a- b = 0
Q ( 3π/5 , 0) -------> (3π/5) a - b = π
R (11π/10 , 0)------> (11π/10) a - b= 2π

sin ((π/10) a- b) = 0
(π/10) a- b = 0
(1) b= (π/10) a
(2) (3π/5) a - b = π
solve equation 1 and 2 simultaneously,
(3π/5) a- (π/10) a = π
cancel π from both sides
(3/5)a - (1/10)a = 1
therefore a= 2 and b = π/5

 

[DANGERBP]

guyz i need a site tht has all core 2 papers ?? i have nothing to solve for tom =S

 

[Professor.Phil]

TAKE IT EASY PPL !!TOMORROWS GRADE BOUNDAY IS 42 FOR A

 

[iblue]

guyz i need a site tht has all core 2 papers ?? i have nothing to solve for tom =S

i need papers 2

 

[DANGERBP]

i need papers 2

were screwed =S

 

[Professor.Phil]

HEY DANGER HOW R YA DOING

 

[¦HaLo¦]

TAKE IT EASY PPL !!TOMORROWS GRADE BOUNDAY IS 42 FOR A

no offense but are u really the examiner ?

 

[iblue]

were screwed =S

im screwed since the c1 exam!!

 

[DANGERBP]

im screwed since the c1 exam!!

ugh man don remind me ! but S1 ughhh **** tht seriously ! -.-

 

[iblue]

ugh man don remind me ! but S1 ughhh **** tht seriously ! -.-

i did mechanics not statistics

 

[iblue]

i was all good at it ! thats just be4 the exam -.- !!! ughhh

story of my life!!

 

[DANGERBP]

story of my life!!

lol =p

 

[gelato]

what about the first part?

 

[gelato]

Oh it's fine; I got it
But I don't get how 15 is not included. I got 15,55,135,175. The marking scheme doesn't count the 15.

 

[U stalking ME]

Oh it's fine; I got it
But I don't get how 15 is not included. I got 15,55,135,175. The marking scheme doesn't count the 15.

yup those are the values and markscheme might be wrong coz we have to include from 0 to 180 so 15 is included :/

 

[moonlight856]

Good luck everyone !
Hope for the best