Any Smart Math People

[keenan87]

Originally Posted by FlamesPuck12

This is Math 30P (Grade 12 Math).
They're only asking for the relationship between the mean and standard deviation in a normal distribution.

The question says: Explain what Janice has to do before sending in her results to head office

Not solve, but explain the relationship between the mean and standard deviation.

Algebraically adjusting the mean and standard deviation isn't part of Math 30 Pure curriculum. (I don't even know if you can adjust mean and standard deviation when the data points aren't given)

Wow man your so smart, thanks a lot for all of your help..but just wondering I am really curious to learn how we can solve that probability with binompdf. For question number 3.

[FlamesPuck12]

Have you learned the calculator functions for this unit?

[keenan87]

Originally Posted by FlamesPuck12

Have you learned the calculator functions for this unit?

Yes I have..


There were actually like 40 questions in th book..3 I didn't get.

[photon]

I wonder if I could figure out what school you're at and send your instructor a link to this thread...

No, that would be abusing my mod powers.. but oh so tempting..

[FlamesPuck12]

Question 6:
Since we are doing proofs, we can only work with one side at a time.
I'll work with the left side. Also, I'll be using x instead of theta, since its easier to type.


(sin² x) / (1 - cos x)

Pythagorean Identity: sin² x + cos² x = 1
Rearrange it so it looks like: sin² x = 1 - cos² x
Substitute it into the proof.

(1 - cos² x) / (1 - cos x)


(1 - cos² x) is difference of squares so factor it out.
(1 - cos² x) = (1 - cos x)(1 + cos x)

[(1 - cos x)(1 + cos x)] / (1 - cos x)


Cancel the like terms and you'll have the following.
1 + cos x


Reciprocal Identity: sec x = (1 / cos x)
Rearrange it so it looks like: cos x = (1 / sec x)
Substitute it into the proof.

1 + (1 / sec x)

Combine both terms into one fraction by multiplying 1 by LCD.

(sec x + 1) / (sec x)


Therefore, sin² x / (1 - cos x) = (sec x + 1) / sec x

[FlamesPuck12]

Question 5:

From the Pure Mathematics 30 Formula Sheet (You do have the formula sheet, right?)
cos(A - B) = cos A cos B + sin A sin B
A = 38°
B = 8°

= cos 30°

Using the 30°-60°-90° special triangle:
cos 30° = SqRt(3) / 2

[keenan87]

Originally Posted by FlamesPuck12

Question 5:

From the Pure Mathematics 30 Formula Sheet (You do have the formula sheet, right?)
cos(A - B) = cos A cos B + sin A sin B
A = 38°
B = 8°

= cos 30°

Using the 30°-60°-90° special triangle:
cos 30° = SqRt(3) / 2

Yeah the problem is that I am taking this course again, and the first time I was never taught this.

[Phanuthier]

I don't mean to be mean, but you got >80% and couldn't solve that problem?

Wasn't that like grade 9 math?

[keenan87]

Originally Posted by Phanuthier

I don't mean to be mean, but you got >80% and couldn't solve that problem?

Wasn't that like grade 9 math?

Lmao, when your teacher says to never worry bout these questions because they are not important, you don't really learn em. In Grade 9, you dont even start Trig where I went to school.

[FlamesPuck12]

What course are you planning to take in university?

[STeeLy]

Originally Posted by keenan87

Here are some Trig Questions:
1.sin(Θ) + cos(Θ)cot(Θ)=csc(Θ)
-State any restrictions to the equation

1. cot(Θ) cannot be undefined. Therefore Θ cannot be any multiples of pi/2 (90 degrees)
Explanation: [cot(Θ)] = [1/tan(Θ)]. tan(Θ) cannot be undefined or zero. At [(pi/2)+n(pi)] (90 degrees + n[180degrees]) where n is any integer, tan(Θ) is undefined. At n(pi) (n[180degrees]), tan(Θ) is zero. Therefore, cot(Θ) at those points would be (1/0) which is undefined.

Originally Posted by keenan87

2.What is the exact value of sin^2(pi/6) - 2sin(pi/6)cos(pi/6) + cos^2(-pi/6)
a)2-(square root of 3)
b)(2-(square root of 3))/2
c)(2+(square root of 3))/2
d)2+(square root of 3)

2. sin(pi/6)=0.5, cos(pi/6) = cos(-pi/6) = rt(3)/2
= 0.5^2 - 2(0.5)(rt(3)/2) + (rt(3)/2)^2
= 0.25 - rt(3)/2 + 3/4
= 1/4 - rt(3)/2 + 3/4
= [1 - rt(3)/2] x 2
= 2 - rt(3)
Answer: a

Originally Posted by keenan87

3.If cos(Θ)= -sin(Θ), then sin^2(Θ) is
a)1/4
b)1/2
c)(square root of 2)/2
d)-(square root of 2)/2

This is best seen with a cos (Θ) and sin (Θ) graph.
You'll find that cos (7pi/4) = -sin (7pi/4). cos (7pi/4) = rt(2)/2. sin (7pi/4) = -rt(2)/2
So sin^2(7pi/4), you have [-rt(2)/2]^2 = 2/4 = 1/2
Answer: b

[keenan87]

Originally Posted by FlamesPuck12

What course are you planning to take in university?

Bio Sciences...Seems like an interesting option

[Phanuthier]

Originally Posted by keenan87

Lmao, when your teacher says to never worry bout these questions because they are not important, you don't really learn em. In Grade 9, you dont even start Trig where I went to school.

Wow, did the education system go into the crapper the past 5 years?

I'm not gonna give you any direct answers, but based on the questions you are asking, I can give you a few hints:

1. stats/probability - always put the question from words into numbers. Thats always the hardest part - interpreting what the question is asking. Unless you speak fluent math, never try and target a problem in words. Once you turn the question from words into numbers, the rest is trivial.

2. trig - obviously, identities. The only way you get better is practice. Better to make mistakes now then on a test. If you need 90 to get into a sci/engg program in university, you are going to need to speak fluent math, so you might as well spend the time now while you have time, rather then university.

[FlamesPuck12]

Originally Posted by keenan87

Bio Sciences...Just want to get scholars advantage along with scholarship money.


So what do you do.

Are you going to U of C?

I'm planning to do engineering at Waterloo next year. Right now, I'm in grade 12 at Bishop Carroll.

[STeeLy]

keenan87, a really simple thing to do before any exam with trigonometry is to draw out the 2 special triangles.

The 90-45-45 (pi/2 - pi/4 - pi/4) Triangle where the two lines that intersect at 90 degrees are 1 and the hypotenuse is rt (2).

Then the 90-60-30 (pi/2 - pi/3 - pi/6) Triangle. Draw an equilateral triangle with all sides as 2, then draw a straight line from one angle to the opposing line. So you have the hypotenuse as 2, your base is 1, and the 90 intersect to the base is rt (3). It will really help you with figuring out what the sin,cos,tan are.

[keenan87]

Originally Posted by Phanuthier

Wow, did the education system go into the crapper the past 5 years?

I'm not gonna give you any direct answers, but based on the questions you are asking, I can give you a few hints:

1. stats/probability - always put the question from words into numbers. Thats always the hardest part - interpreting what the question is asking. Unless you speak fluent math, never try and target a problem in words. Once you turn the question from words into numbers, the rest is trivial.

2. trig - obviously, identities. The only way you get better is practice. Better to make mistakes now then on a test. If you need 90 to get into a sci/engg program in university, you are going to need to speak fluent math, so you might as well spend the time now while you have time, rather then university.

Stats for the most part is easy. However, Identities is something I have termendous problems with.

[keenan87]

Originally Posted by STeeLy

keenan87, a really simple thing to do before any exam with trigonometry is to draw out the 2 special triangles.

The 90-45-45 (pi/2 - pi/4 - pi/4) Triangle where the two lines that intersect at 90 degrees are 1 and the hypotenuse is rt (2).

Then the 90-60-30 (pi/2 - pi/3 - pi/6) Triangle. Draw an equilateral triangle with all sides as 2, then draw a straight line from one angle to the opposing line. So you have the hypotenuse as 2, your base is 1, and the 90 intersect to the base is rt (3). It will really help you with figuring out what the sin,cos,tan are.

Thanks for the advice

[keenan87]

Originally Posted by FlamesPuck12

Are you going to U of C?

I'm planning to do engineering at Waterloo next year. Right now, I'm in grade 12 at Bishop Carroll.

Wow, you are really smart haha

Waterloo is a great school

[FlamesPuck12]

Originally Posted by keenan87

Wow, you are really smart haha

Waterloo is a great school

Yeah I heard its a good school, but they take forever giving out admission.
Anyway have you got yours yet? Are you planning to go to U of C?

[keenan87]

4. Solve sin2y=cos4y for y, where 0<y<360. Hint (cos4y=cos(2y+2y))

Also just wondering guys, this question was worth a lot and I just want to make sure if I am on the right track.

In Saskatchewan, the sun rises at 09:17 on December 21 and at 04:35 on June 22. Because there is no daylight savings time in Saskatchewan, the time the sun rises on any other day can be predicted from a sinusodial graph with a period of 365 days.

Write a sinusoidal equation that realtes the time the Sun rises to the day of the year.

I got
y=2.35cos(2pi/365)(x-173)+6.933

is this the right way?

Some other questions (I need to hand in the entire course haha)
1.To play a game, a die is rolled to see who plays first. Four players are goig to play the game. What is the probability that atleast two people roll the same number? Express your answer to the nearesr tenth of a percent.

2.Zayra wrote a computer program that randomely printed the letters of the words given to it. The program is given the word REPEAT. What is the probability that it prints out the letters so they spell the word Repeat? Round your answer to 4 decimal places.
---I went 6!/2! =360 ways in total...and then I am not sure if there is only one way I use to spell the word or two ways considering there are two "E"'s. Should i go 1/360 or 2/360?

3.There are 12 feathered shuttlecocks and 9 plastic ones in a bag. If two shuttles are pulled from the bag without replacement, determine the probability:
a)1 plastic and then 1 feathered
---would we go (12P1 X9P1)/21P2?

b)1 plastic and 1 feathered
---would I go (12C1 X 9C1)/21C2

C)Atleast 1 plastic
----would I go ((12C1 X 9C1) + (12C0 X 9C2))/21C2


After, this I am done everything..