Maths, Addmaths and Statistics: Post your doubts here!

[Faizan Muhammmad]

oh, yes, we'll have to make an eq first, right?

no man any way it isnt possible
dont they say differentiate with respect to x in questions
you can differentiate one variable only

 

[M.Omar]

no man any way it isnt possible
dont they say differentiate with respect to x in questions
you can differentiate one variable only

Some queries:
Shud we draw or sketch diagrams in say questions like tht of velocity and other relevant questions and also label them clarity and to refer in later part of out answer
Also in bin exp shud we write the coefficient in Combination form or column form i.e (n (above) r(below)

 

[***amd***]

no man any way it isnt possible
dont they say differentiate with respect to x in questions
you can differentiate one variable only

suppose if we have something like, y = 5cosx + 2cosy
we shall make y the subject first, no?

 

[Faizan Muhammmad]

suppose if we have something like, y = 5cosx + 2cosy
we shall make y the subject first, no?

yep but how ?
I am pretty sure not in olevels

 

[Faizan Muhammmad]

Some queries:
Shud we draw or sketch diagrams in say questions like tht of velocity and other relevant questions and also label them clarity and to refer in later part of out answer
Also in bin exp shud we write the coefficient in Combination form or column form i.e (n (above) r(below)

its very good to draw diagrams
dont think it matters for bin exp but use above and below if you can

 

[***amd***]

yep but how ?
I am pretty sure not in olevels

yes, it isnt.

 

[M.Omar]

its very good to draw diagrams
dont think it matters for bin exp but use above and below if you can

Thnx and is it also pertinent to draw sketches in questions like when there is a sector of circle given and a chord and since the radii form an isosceles triangle we cud find the chord by drawing a perpendicular frm the centre to the chord and then apply trig functons so we shud also draw diagrams to illustrate the perpendicular bisector as well,right?
Also in plotting str line graphs frm non linear eq shud we draw a table of values for Y and X whtever they may be evn though the question just says to draw the str line on graph?

 

[afrolina]

How is the preparation for add math?

 

[Faizan Muhammmad]

Thnx and is it also pertinent to draw sketches in questions like when there is a sector of circle given and a chord and since the radii form an isosceles triangle we cud find the chord by drawing a perpendicular frm the centre to the chord and then apply trig functons so we shud also draw diagrams to illustrate the perpendicular bisector as well,right?
Also in plotting str line graphs frm non linear eq shud we draw a table of values for Y and X whtever they may be evn though the question just says to draw the str line on graph?

its good to draw diagrams, if you make a mistake the examiner can see what you were doing
the table is nearly necessary for complex equations but for simple linear ones there is no need

 

[M.Omar]

its good to draw diagrams, if you make a mistake the examiner can see what you were doing
the table is nearly necessary for complex equations but for simple linear ones there is no need

Also for proving trig identities is there any definite rule to have followed the MS..I mean coz there may be many diff methods so wht do u reckon..will they give FULL marks if we do arrive at the solution ....any suggestion abt this which u many have heard of or suggest urself
Btw how is ur prep goin

 

[M.Omar]

its good to draw diagrams, if you make a mistake the examiner can see what you were doing
the table is nearly necessary for complex equations but for simple linear ones there is no need

And also abt those questions in which they ask us to draw linear graphs and thus find unknown constants .In this question since it is highly unlikely to get correct answers in higher degrees like 0.00546 or like tht shud we write the answers to 1 d.p or still 3 sig fig like 0.403 or 0.40 or 0.4?
Thnx a bunch

 

[***amd***]

How is the preparation for add math?

good, Alhamdulillah.
wbu?

 

[AbbbbY]

What is the differnentiation of 5cosx + 2cosy ???

-5 sinx - 2 siny

not possible....not same variable

No this cant be ...simple as tht

d/dx 5cosx + 2cosy = -5sinx-2siny(dy/dx)(x)

That said, I don't think implicit differentiation is a part of Add Math.

 

[AbbbbY]

Also for proving trig identities is there any definite rule to have followed the MS..I mean coz there may be many diff methods so wht do u reckon..will they give FULL marks if we do arrive at the solution ....any suggestion abt this which u many have heard of or suggest urself
Btw how is ur prep goin

Doesn't matter. That's the beauty of math. Irrespective of the method taken, if the answer is correct, you get the mark provided you haven't made up steps/eaten steps.
For me, I always changed the equation to sin and cos only before trying any identities, as such. Worked wonders for me in Add Math and AS Math.

And also abt those questions in which they ask us to draw linear graphs and thus find unknown constants .In this question since it is highly unlikely to get correct answers in higher degrees like 0.00546 or like tht shud we write the answers to 1 d.p or still 3 sig fig like 0.403 or 0.40 or 0.4?
Thnx a bunch

3sf is preferred as far as I remember. Apart from angles, where 1 dp is required, all of A Level math had 3sf. I'm not sure if it's different for Add Math, although it shouldn't be.

 

[AbbbbY]

Also for proving trig identities is there any definite rule to have followed the MS..I mean coz there may be many diff methods so wht do u reckon..will they give FULL marks if we do arrive at the solution ....any suggestion abt this which u many have heard of or suggest urself
Btw how is ur prep goin

Doesn't matter. That's the beauty of math. Irrespective of the method taken, if the answer is correct, you get the mark provided you haven't made up steps/eaten steps.
For me, I always changed the equation to sin and cos only before trying any identities, as such. Worked wonders for me in Add Math and AS Math.

And also abt those questions in which they ask us to draw linear graphs and thus find unknown constants .In this question since it is highly unlikely to get correct answers in higher degrees like 0.00546 or like tht shud we write the answers to 1 d.p or still 3 sig fig like 0.403 or 0.40 or 0.4?
Thnx a bunch

3sf is preferred as far as I remember. Apart from angles, where 1 dp is required, all of A Level math had 3sf. I'm not sure if it's different for Add Math, although it shouldn't be.

 

[M.Omar]

3sf is preferred as far as I remember. Apart from angles, where 1 dp is required, all of A Level math had 3sf. I'm not sure if it's different for Add Math, although it shouldn't be.[/quote]
But in questions like a straight line graph which we have to draw from non linear equation like y=AB^x and then we convert it to form to make it suitable for drawing straight line graph....now they will also ask to calculate values of A and B ...since it,s highly unlikely to get higher degress tht is better accuracy like 0.411 ...to how many sf shud we write is it 0.4 0.41 or 0.411 still? ...only for this type of question?
AbbbbY

 

[M.Omar]

And also http://papers.xtremepapers.com/CIE/...matics - Additional (4037)/4037_s13_ms_11.pdf
Look at 9 ii in which they have expressed 2/5c -a/4 -3b/4 separately without any oe or anything
cudn,t it be written with common denominator like 20 in this case and the values claculated frm tht accordingly...I mean this shud also be correct ?

 

[afrolina]

good, Alhamdulillah.
wbu?

Not good at all!! but I'm still glad about my preperation...
So Alhamdulillah!

 

[Faizan Muhammmad]

Also for proving trig identities is there any definite rule to have followed the MS..I mean coz there may be many diff methods so wht do u reckon..will they give FULL marks if we do arrive at the solution ....any suggestion abt this which u many have heard of or suggest urself
Btw how is ur prep goin

no probs at all , the point is getting the LHS=RHS
prep is ok, got EM with it too

 

[Faizan Muhammmad]

And also abt those questions in which they ask us to draw linear graphs and thus find unknown constants .In this question since it is highly unlikely to get correct answers in higher degrees like 0.00546 or like tht shud we write the answers to 1 d.p or still 3 sig fig like 0.403 or 0.40 or 0.4?
Thnx a bunch

yes you should, try putting the equation you made in calculator and test values already given with it
from that decide whether to round or not