Maths, Addmaths and Statistics: Post your doubts here!

[CaptainDanger]

http://www.xtremepapers.com/CIE/Cambridge O Levels/4024 - Mathematics/4024_s08_qp_2.pdf ok my problem is in qustion 1 how do i convert m^2 to m^3

Convert the diameter from centimeters to meters first... Then find it out... Volume is in cubic meters...

 

[zeshan huq]

Convert the diameter from centimeters to meters first... Then find it out... Volume is in cubic meters...

thanx very much that solves my problem

 

[leosco1995]

How to find the nth term for this sequence
4,12,32,70...............

This question is the one from J07 right? If so, you are supposed to use the additional information provided in the question:

The first terms of S and T are 3 and 4..........difference = 1.
The second terms are 10 and 12..................difference = 2.
The third terms are 29 and 32.....................difference = 3.
The fourth terms are 66 and 70..................difference = 4.

See the difference here? T = S + n (n being the term number). The formula of S is n³ + 2. Since T = S + n, T = (n³ + 2) + n.

 

[doctormani]

This question is the one from J07 right? If so, you are supposed to use the additional information provided in the question:

The first terms of S and T are 3 and 4..........difference = 1.
The second terms are 10 and 12..................difference = 2.
The third terms are 29 and 32.....................difference = 3.
The fourth terms are 66 and 70..................difference = 4.

See the difference here? T = S + n (n being the term number). The formula of S is n³ + 2. Since T = S + n, T = (n³ + 2) + n.

sorry didnt got it??

 

[leosco1995]

OK, I'll try to be more clear. It IS question 3 of J07, right?

The question says "By comparing S and T, write down
...
(b) an expression, in terms of n, for the n th term of T."

Read the bolded part. You are supposed to compare the terms of S with the terms of T. I did that in my above post, check it out.

As you can see, the difference between the values of S and T is 1 for the 1st term, 2 for the 2nd term, 3 for the 3rd term, and so on. Using that statement, can I say the value of T is the value of S + the term number? In other words, T = S + n?

Since S is already given as n³ + 2, we can substitute it in the above equation:

T = (n³ + 2) + n
T is therefore = n³ + n + 2

I hope you got it this time. If it is still confusing, please tell me what part you don't get.

 

[doctormani]

Ohh yea i got it i actually i didnt read the ques so didnt get it now i understood

 

[leosco1995]

OK, great.

 

[ROCK THE FIRST]

Correction...............This question is from 2005 Oct/Nov Paper 1 Q6

 

[Irtza]

how is (x+1)(x-3)<0 makes -1<x<3 not x<-1 or x<3 why does he changes the sign we are not multiplying or dividing by -ve he makes x<-1 to x>-1 plz how the complete working a explain

 

[SalmanPakRocks]

(x+1) (x-3) < 0
x^2 -3x + x - 3 <0
x^2 -2x - 3 <0
x <-1 or x <3

 

[Irtza]

(x+1) (x-3) < 0
x^2 -3x + x - 3 <0
x^2 -2x - 3 <0
x <-1 or x <3

why x <-1 it should be -1<x

 

[SalmanPakRocks]

solve it quadratically.
we don't have two inequalities here.
there are two possible value of x so u can't assume its as < or > .

 

[Irtza]

solve it quadratically.
we don't have two inequalities here.
there are two possible value of x so u can't assume its as < or > .

x^2 -2x - 3 <0
x^2 -3x+1x- 3 <0
x(x-3)+1(x-3)<0
(x+1)(x-3)<0
(x+1)<o or (x-3)<0
x<-1 OR x<3 but this is the wrong answer the book says answer is -1<x<3

 

[Irtza]

-1<x<3 is not equal to x<-1 OR x<3

 

[CaptainDanger]

x^2 -2x - 3 <0
x^2 -3x+1x- 3 <0
x(x-3)+1(x-3)<0
(x+1)(x-3)<0
(x+1)<o or (x-3)<0
x<-1 OR x<3 but this is the wrong answer the book says answer is -1<x<3

Which book is it?

 

[Irtza]

new additional math by ho soo thong and khor nayak hiong

 

[Irtza]

is it a rule that x-1<0 then x>1 it cant be but...

 

[CaptainDanger]

is it a rule that x-1<0 then x>1 it cant be but...

No. You have to see the greater than or less than sign then make domain accordingly after finding out the roots ...

When you find out the x values those are the roots of the equation...
See the range for the question... It is less than zero and x^2 has positive coefficient... Make a sketch of it...

Less than zero shows that you have to take y values which are less than zero for this equation... Its the range... So x values have to be from the shaded part... When you take those so domain has to be less than 3 and greater than -1... x is domain... y is range...

 

[legion]

Find the value of 'n' if the reciprocal of 2^3 is equal to 2^n.

 

[Irtza]

n=-3