[Xarren]

(Original post by Hamburglar)
Okay thanks for the help guys. I think my main issue was that it was the only time I'd really seen a straight line equation give like that, so I was getting confused. :/

-1, -1, rt2

[Braniac101]

(Original post by Moiraclaire)
you could end up with 96 and 83 like I did first time round , don't get too complacent and slip up ! And do not put any working (not matter how insignificant you think it is) in the margin. My advice to the world.

thanks for the advice, but i have 86 already
also i think my score is in fact 100- just being a little modest
but yh as u sed, better sure than sorry

[Xarren]

(Original post by Dreamester)
Hey guys, when we're solving 1st order DE, we should do whole work showing that when I.F = x then xy = integral of (x*Q) where Q is another function, or simply state:

I.F = x ;
yx= integral (x*Q)

will score all marks?

There is usually one mark for showing e^int(f(x))

[Moiraclaire]

(Original post by elkana)
they did y²=r²sin²
then subbed in r² and differentiated
2y(dy/do) =0 as well

surely that does not work as y could be zero and then we wouldn't know.

[Tyron3]

Need 86 in this or FP3 hopefully it doesn't have a nasty complex numbers question.

[Dat Guy]

(Original post by TenaciousMonkey)
How have you come to the line w = ((x+1) +xi)...?

z = x + xi
sub it in the equation for w

[desijut]

(Original post by elkana)
does anyone know which types of graphs we are expected to know haw to draw?

just do what i do and make a table of values (theta =0,pi/4,pi/2, etc) it's never failed me.

[fiona23]

Do we have to know how to do prove by induction??

[Dreamweaver]

(Original post by fiona23)
Do we have to know how to do prove by induction??

Yes it can come up but it's unlikely.

[Rory_M]

http://www.edexcel.com/migrationdocu...e_20090619.pdf

June 2009 q6b), I drew the circle ok, but why is R the area OUTSIDE?? I shaded inside and said that was R but I think the MS is saying R is on the outside of the circle...

Also with 2nd ODE if the RHS is cos3x for example then you use PI Acos3x+Bsin3x yes? so the number in front of x stays the same?
Same q for RHS being 2e^(-x) it the PI always Ae^(-x) only, and only if A=2 do you use Axe^(-x) yes?

Thanks

EDIT: found solution to 6b) if anyone else was wondering from the 2009 thread. Basically as mod z < 3, just insert the equality sign into your circle then pick a point (say centre) if it agrees with the inequality shade that region, if it doesn't then shade the other region (in this case the outside of the circle).

[number23]

(Original post by Rory_M)
http://www.edexcel.com/migrationdocu...e_20090619.pdf

June 2009 q6b), I drew the circle ok, but why is R the area OUTSIDE?? I shaded inside and said that was R but I think the MS is saying R is on the outside of the circle...

Also with 2nd ODE if the RHS is cos3x for example then you use PI Acos3x+Bsin3x yes? so the number in front of x stays the same?
Same q for RHS being 2e^(-x) it the PI always Ae^(-x) only, and only if A=2 do you use Axe^(-x) yes?

Thanks

for 2nd order differential you keep the bit around the x, so youre right.. you just change the coefficant

[Rory_M]

(Original post by number23)
for 2nd order differential you keep the bit around the x, so youre right.. you just change the coefficant

Wicked thanks, that suddenly makes them alot easier! I was using a PI like Ae^Bx...

[TenaciousMonkey]

Can someone explain how to do this? The mark scheme gives the answer but doesn't show the method. Thanks in advance!

[number23]

A few questions, would really appreciate help:

• how do you solve, or show graphically this complex inequality: ?
• how do you solve a complex transformation like: ?
• the syllabus says 'derivation of the series expansion of etc. does this just mean, differentiating and putting in f(0), f'(0) etc?
• how do you sketch: and ?

thanks

[number23]

(Original post by TenaciousMonkey)


Can someone explain how to do this? The mark scheme gives the answer but doesn't show the method. Thanks in advance!

draw the graph of two on an argand diagram, then consider the point they intersect

[physics1]

(Original post by number23)
A few questions, would really appreciate help:

• how do you solve, or show graphically this complex inequality: ?
• how do you solve a complex transformation like: ?
• the syllabus says 'derivation of the series expansion of etc. does this just mean, differentiating and putting in f(0), f'(0) etc?
• how do you sketch: and ?

thanks

Right starting from the top
*The graph of th Loci which meets (z-a)=(z-b) is the perpeniduclar bisector of the points b and a. So less than or equal to will be the LHS of the graph.
*Depends what z=? but generally i make z the subject and then sub in U+iV for for W and seperate the real and imaginary parts. Real parts=x Imaginary parts =y.
*yes
*Where did u see this? but basically using b as theta as im lazy you get p=rcos(b)cosa+rsin(b)sina
p=cos(a)x+sin(a)y which is a straight line with gradient whatever depending on whatever a is. (gradient = cot(a) cutting y axis as p/sin(a))
*For this as the cartesian method makes a horrible graph of (x^2+y^2)^2=a^2(x^2-y^2) i would plot points.

[physics1]

Did u see i also posted the answer to the one u asked me last time ?

[number23]

(Original post by physics1)
Right starting from the top
*The graph of th Loci which meets (z-a)=(z-b) is the perpeniduclar bisector of the points b and a. So less than or equal to will be the LHS of the graph.
*Depends what z=? but generally i make z the subject and then sub in U+iV for for W and seperate the real and imaginary parts. Real parts=x Imaginary parts =y.
*yes
*Where did u see this? but basically using b as theta as im lazy you get p=rcos(b)cosa+rsin(b)sina
p=cos(a)x+sin(a)y which is a straight line with gradient whatever depending on whatever a is. (gradient = cot(a) cutting y axis as p/sin(a))
*For this as the cartesian method makes a horrible graph of (x^2+y^2)^2=a^2(x^2-y^2) i would plot points.

thanks for the help, all those graphs are in the syllabus

if they ask you to sketch poalr graphs, do you have to sketch them as cartesians?

[physics1]

(Original post by number23)
thanks for the help, all those graphs are in the syllabus

if they ask you to sketch poalr graphs, do you have to sketch them as cartesians?

Right iv seen alot of people ask this but for any equasion the cartesian graph looks like polar graph! so if in doubt find the graph using a cartesian method then just dont draw the y axis and u have a polar graph

[physics1]

(Original post by number23)
thanks for the help, all those graphs are in the syllabus

if they ask you to sketch poalr graphs, do you have to sketch them as cartesians?

Can u link me to the syllabus notes please