Mathematics: Post your doubts here!

[iKhaled]

Exactly!! If it started from the origin, then 'a' would have been equal to 9. You could tell that just by looking at the graph.

tankkkkk uuuuuuuuuu

 

[hm12]

http://www.xtremepapers.com/papers/...S Level/Mathematics (9709)/9709_w11_qp_12.pdf
http://www.xtremepapers.com/papers/...S Level/Mathematics (9709)/9709_w11_ms_12.pdf
please explain question 3 part (iii)

@dug : can you help me with this.thanks

 

[Dug]

http://www.xtremepapers.com/papers/...S Level/Mathematics (9709)/9709_w11_qp_12.pdf
http://www.xtremepapers.com/papers/...S Level/Mathematics (9709)/9709_w11_ms_12.pdf
please explain question 3 part (iii)

@dug : can you help me with this.thanks

There is no part 3 to that question.

 

[Raiyan3]

Can anyone please give me notes or explain the topic of Range and Domains! i still have no idea about it

 

[Jimmy Russels]

Guys, can somebody please help me? This is the third time I'm asking this.

Qs.1) Find the values of k such that the straight line y=2x+k meets the curve with equation x^2+2xy+y^2=5 exactly once.

Qs.2) An Open cylindrical wastepaper bin, of radius r cm and capacity Vcm^3 is to have a surface area of 5000 cm^3.
(a) Show that V=1/2r(5000πr^2)
(b) Calculate the maximum possible capacity of the bin.

Qs.3) Find the equation of the normal to the curve y=8/1-x^3 at the point (-1,4)

 

[roadtrip9o9]

I Have the only thing remaining is functions and as 2 days are left i cant get it from any book thats y i asked u

 

[Dug]

Guys, can somebody please help me? This is the third time I'm asking this.

Qs.1) Find the values of k such that the straight line y=2x+k meets the curve with equation x^2+2xy+y^2=5 exactly once.

Qs.2) An Open cylindrical wastepaper bin, of radius r cm and capacity Vcm^3 is to have a surface area of 5000 cm^3.
(a) Show that V=1/2r(5000πr^2)
(b) Calculate the maximum possible capacity of the bin.

Qs.3) Find the equation of the normal to the curve y=8/1-x^3 at the point (-1,4)

In Q2, isn't it V=1/2r (5000-pi r^2)

 

[Jimmy Russels]

In Q2, isn't it V=1/2r (5000-pi r^2)

Yes sorry! My mistake.

 

[Dug]

I Have the only thing remaining is functions and as 2 days are left i cant get it from any book thats y i asked u

Ok lets see...Try asking one question at a time. I mean divide your problems as that would make it easier for me to answer and for you to understand.

 

[Dug]

Yes sorry! My mistake.

For Q2:
S.A=2πrh + πr^2
2πrh + πr^2 = 5000
h = (5000-πr^2)/2πr

V=πr^2h
V=πr^2 [(5000-πr^2)/2πr]
V=2500r - πr^3 / 2
V=(1/2)(r)(5000-πr^2)

 

[Spunkyfarhan]

For Q2:
S.A=2πrh + πr^2
2πrh + πr^2 = 5000
h = (5000-πr^2)/2πr

V=πr^2h
V=πr^2 [(5000-πr^2)/2πr]
V=2500r - πr^3 / 2
V=(1/2)(r)(5000-πr^2)

CAN U TELL ME IN OLEVEL LOCI THERE IS QUESTION BISECT LINE ABC?

 

[Esme]

@roadtrip9o9
Core maths has some really good explanations for functions and graphs. min and max is also eplained well in that book.i suggest you get that. You'l waste time here. and wont get the whole picture.

 

[Dug]

Guys, can somebody please help me? This is the third time I'm asking this.

Qs.1) Find the values of k such that the straight line y=2x+k meets the curve with equation x^2+2xy+y^2=5 exactly once.

Qs.2) An Open cylindrical wastepaper bin, of radius r cm and capacity Vcm^3 is to have a surface area of 5000 cm^3.
(a) Show that V=1/2r(5000πr^2)
(b) Calculate the maximum possible capacity of the bin.

Qs.3) Find the equation of the normal to the curve y=8/1-x^3 at the point (-1,4)

For Q2 part b
Set dV/dr = 0
You get r = 530.5
Find an expression for second derivative and insert this value of r.If you get a maxima with this value, put this value in the v=1/2r(5000-πr^2). I don't know if its correct. Whats the answer for this question?

 

[Dug]

CAN U TELL ME IN OLEVEL LOCI THERE IS QUESTION BISECT LINE ABC?

Sorry, I couldn't get you.

 

[Dug]

@roadtrip9o9
Core maths has some really good explanations for functions and graphs. min and max is also eplained well in that book.i suggest you get that. You'l waste time here. and wont get the whole picture.

Are you implying that i am wasting his time?

 

[hm12]

There is no part 3 to that question.

i mean part(ii) sorry

 

[roadtrip9o9]

LOL my board exam is on tuesday ... atleast help a little -.-

 

[Jimmy Russels]

For Q2 part b
Set dV/dr = 0
You get r = 530.5
Find an expression for second derivative and insert this value of r.If you get a maxima with this value, put this value in the v=1/2r(5000-πr^2). I don't know if its correct. Whats the answer for this question?

The answer is 38500 cm^3.

 

[Dug]

Guys, can somebody please help me? This is the third time I'm asking this.

Qs.1) Find the values of k such that the straight line y=2x+k meets the curve with equation x^2+2xy+y^2=5 exactly once.

Qs.2) An Open cylindrical wastepaper bin, of radius r cm and capacity Vcm^3 is to have a surface area of 5000 cm^3.
(a) Show that V=1/2r(5000πr^2)
(b) Calculate the maximum possible capacity of the bin.

Qs.3) Find the equation of the normal to the curve y=8/1-x^3 at the point (-1,4)

For Q3)
dy/dx = 8(1-x^3)^(-1-1) (-1) (-3x^2)
dy/dx = 24x^2/(1-x^3)^2
Inserting x = -1
dy/dx = 24(-1)^2 / (1-(-1)^3)^2
dy/dx = 24/4
dy/dx = 6

Eq of the normal :-
Gradient of the normal = -1/6
4=-1(-1/6) + c
c = 23/6
y = -1/6x + 23/6

Again, the accuracy of my answers is not guaranteed.

 

[Dug]

The answer is 38500 cm^3.

Wait...rechecking