~~Mathematics Revising Game~~ (1 Viewer)

[lyounamu]

The rule of this game is to get the whatever question that is posted, and post another question. Then another member comes in, answer the question and post another question so that the chain reaction can continue over and over again.

I will start with easy one:

A farmer found that probability that a planted seedling will eventually bear fruit was 0.85. He planted "n" number of seedlings.

i) what's the probability that no seedling will bear fruit?
ii) how many seedlings must be planted to ensure 99% certain that at least one seedling will bear fruit?

By the way, make sure you got all the answers ready when you post up a question. If not, there is not much point to this exercise. Good luck~

EDIT:


PLEASE POST ONLY 2 UNIT QUESTIONS. This is 2 unit forum so we only want 2 unit level questions. NO 4 UNIT OR 3 UNIT HERE.

Thank you.

 

[PC]

(i) 0.15ⁿ
(ii) 3 seedlings

Next question:
The region by the curve y = ln x, the co-ordinate axes, and the line y = ln 2 is rotated about the y-axis. Find the volume of the solid so formed.

 

[lionking1191]

1.5 pi u^3

find the equation of the line passing through the intersection of the equations y=x+1 and y= -2x -1 which also passes through the point (2,4)

 

[AkaiHanabi]

1.5 pi u^3

find the equation of the line passing through the intersection of the equations y=x+1 and y= -2x -1 which also passes through the point (2,4)

God damn. Stupid fractions. gah

11x - 8y +10 = 0

I hope that's right.

Use mathematical induction to prove that

1 + 3 + 6 + ... + 1/2(n)(n+1) = 1/6(n+1)(n+2) for all integers n = 1, 2, 3 ....

 

[bored of sc]

Wait: you're right AkaiHanabi.

 

[lyounamu]

God damn. Stupid fractions. gah

11x - 8y +10 = 0

I hope that's right.

Use mathematical induction to prove that

1 + 3 + 6 + ... + 1/2(n)(n+1) = 1/6(n+1)(n+2) for all integers n = 1, 2, 3 ....

this is 2 unit maths forum...i don't think anyone who only do 2 unit would know that...

 

[AkaiHanabi]

I got x-3y-3 = 0 for the coordinate geometry one posted by lionking1191.

Oh damn.

y = x+1
y= -2x -1
x+1=-2x-1
3x=-2
x=-2/3
y=-2/3+1
y=1/3

(y-4)/(x-2)=(1/3-4)/(-2/3 - 2)
(y-4)/(x-2)=11/8
8(y-4)=11(x-2)
8y - 32 = 11x -22
11x - 8y +10 = 0

 

[bored of sc]

Simplify cotxsecx.

 

[AkaiHanabi]

this is 2 unit maths forum...i don't think anyone who only do 2 unit would know that...

Oh woops. Sorry >< try:

Find the limiting sum of the series 1000 + 100 +10 + ...

 

[lionking1191]

lol see edit akai.

ps. i pulled the numbers out of air, so too bad with the fractions :uhhuh:

 

[bored of sc]

Oh damn.

y = x+1
y= -2x -1
x+1=-2x-1
3x=-2
x=-2/3
y=-2/3+1
y=1/3

(y-4)/(x-2)=(1/3-4)/(-2/3 - 2)
(y-4)/(x-2)=11/8
8(y-4)=11(x-2)
8y - 32 = 11x -22
11x - 8y +10 = 0

Don't worry, you were correct.

 

[lyounamu]

Simplify cotxsecx.

cosec

question is posted by akaihanabi.

 

[bored of sc]

Oh woops. Sorry >< try:

Find the limiting sum of the series 1000 + 100 +10 + ...

1111.111111..... recurring? I haven't done this topic yet.

 

[lionking1191]

Oh woops. Sorry >< try:

Find the limiting sum of the series 1000 + 100 +10 + ...

10,000/9

Simplify cotxsecx.

cosec x

edit: forgot question

find the size of each internal angle in a decagon

 

[bored of sc]

cosec

question is posted by akaihanabi.

Oh sorry.

 

[lyounamu]

Oh woops. Sorry >< try:

Find the limiting sum of the series 1000 + 100 +10 + ...

a/(1-r)

= 1000/(1-1/10) = 10000/9

my following question is pretty unique. But try this out:

http://www.boredofstudies.org/courses/maths/2u/2001_Maths2_T_Abbotsleigh_q.pdf

10(b)

10,000/9



cosec x

edit: forgot question

find the size of each internal angle in a decagon

assuming that it is regular decagon?

each angle:

((n-2) x 180)/ n = 144

 

[lyounamu]

Hey, guys I justed edited opening statement.

We only want 2 unit questions guys. This is 2 unit forum and I expect that 2 unit students are not capable of solving 3 unit topic questions as they would not know the 3 unit materials. Thanks.

 

[Azreil]

AD = hyp of triangle ADC
AD^2 = CD^2 + AC^2
CD^2 = DE^2 - CE^2
therefore AD^2 = DE^2 - CE^2 + AC^2
AE = CE (diagonals of a parallelogram bisect each other)
AE^2 = CE^2
And AC = AE + CE = 2AE
AC^2 = 4AE^2
AD^2 = DE^2 - AE^2 + 4AE^2
= DE^2 + 3AE^2

Four cards are chosen from a regular pack of cards and placed side by side on the table. What is the probability that these four cards are all from different suits?

 

[Graceofgod]

Four cards are chosen from a regular pack of cards and placed side by side on the table. What is the probability that these four cards are all from different suits?

39/51 * 26/50 * 13/49 = 2197/20825 = 8.443 * 10^-7 (4s.f.)

Question = find d(sec^2(x))/dx.

EDIT: Thanks to syriangabsta for pointing out my mistake.

 

[tommykins]

回复: Re: ~~Mathematics Revising Game~~

2sec^2.tanx