i know that there is the difference of two squares for quadratics, but what about cubics? is there a rule?

do we have to go through the long process of polynomial div?

Reply 3108

sahjan

Original post by überambitious_ox

how do you factorise this?

image:

i know that there is the difference of two squares for quadratics, but what about cubics? is there a rule?

do we have to go through the long process of polynomial div?

If you're trying to find x, make it x^3=8 and then cube root of 8 so x=2
It doesn't look like you can factorise it...there's no common factor :s-smilie:

Reply 3109

sahjan

Original post by yaboy

whats triple angles :confused:

cos3x and sin3x where you have to split them up into cos(2x+x) and sin(2x+x) :smile:

(edited 10 years ago)

Reply 3110

orange94

Original post by yaboy

whats triple angles :confused:

Lool I don't think it's the actual name!!! Take a look at January 2007 first question. Sin3x= sin(sin2x + sinx)

You just use the Sin(A+B) formula
To get Sin2xCosx+SinxCos2x

Then sub in the double angle formula for Sin2x and Cos2x!

Just look at the question and look at exam solutions video on applications- Triple angle!

Fairly straight forward just apply what you already understand!

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Reply 3111

orange94

Gonna defo stop by Starbucks before I go school in the morning!!! Lol this all nighter is gonna kill me in the morn! Good luck y'all!!! Now I'm gonna sleep now

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Reply 3112

PoorLoser

all nighters before a maths exam (esp. c3) isn't good!

just sleep for at least 2-3 hours before the exam

and I wouldn't suggest learning too many new things...

just did a c4 paper, and I'm well tired now D:

Good luck with C3 tomorrow guys btw!

(btw, is it a morning or afternoon exam?)

Reply 3113

HeyThereEveryone

I think I'm prepared-that's what I said in January :frown:

now I know I'm prepared :smile:

Reply 3114

LegendX

2 exams tomorrow and trying to do an all nighter, the story of my life....

Reply 3115

PoorLoser

Original post by LegendX

2 exams tomorrow and trying to do an all nighter, the story of my life....

what other exam do you have?

Reply 3116

Pitfak

Just divide it by (x-2) algebraically. (X-2)(x2 +2x+4)' .,

Original post by überambitious_ox

how do you factorise this?

image:

i know that there is the difference of two squares for quadratics, but what about cubics? is there a rule?

do we have to go through the long process of polynomial div?

Reply 3117

LegendX

Original post by PoorLoser

what other exam do you have?

Edexcel physics unit 4. Also, anyone know how to do this question?

image.jpg357.7KB

Reply 3118

Pitfak

Original post by Revisionbug

Sh** i dont know how to work out values such as arcos something like arcos30 without a calculator anymore is there a easy way of doing it infact i cant even do it for cos30 i know cos45 cos90 sin0 basic stuff like that but when tryin to work out without a calculator another value i dont know how to do it

Are you sure you mean arcos30? Or arcos0.5, for example. Which is 60. Arcos 0.5 means cos^-1 (0.5)=...

You may be asked to find sin(arcos(4/5)) then you find that cosx = 4/5, therefore sinx = 3/5, which is the required answer.