VCE Methods Question Thread!

[knightrider]

^ seems legit

Both probabilities look OK according to my Classpad.

Thanks so much guys 

plato since you use the classpad could you help me with this issue?

How come when i antidifferentiate by hand i get

but when i  antidifferentiate using the CAS i get  ?

I am using the casio classpad 400.

Does you know whats wrong with my CAS?

Thanks 

[knightrider]

Say if we got this question in an exam and it was worth 2 marks .How would we have to set out our working out?

Find the value of c in the following, correct to 3 decimal places.

Pr(Z ≥ c) = 0.45

[@#035;3]

Hey guys quick question; thanks in advance

The temperature inside a hothouse is controlled so that sensitive plants can survive. The temperature, T degrees C, at time t hours after 8 am is given by the equation
T= 22+3*sin(pi*t/12). On one particular day the temperature outside the house, E degrees C, is given by E= 19+8*sin(pi*t/12)

Find the time(s), correct to the nearest minute, on this day when the temperatures inside and outside the hothouse are equal. 

cheers

[@#035;3]

Sorry I worded the question incorrectly it does say "The bullseye or the region". sorry about that!
parts a + b are correct though!

[Peanut Butter]

Sorry I worded the question incorrectly it does say "The bullseye or the region". sorry about that!
parts a + b are correct though!

If the questions says "or", you just need to add the two probabilities together

[Floatzel98]

Hey guys quick question; thanks in advance

The temperature inside a hothouse is controlled so that sensitive plants can survive. The temperature, T degrees C, at time t hours after 8 am is given by the equation
T= 22+3*sin(pi*t/12). On one particular day the temperature outside the house, E degrees C, is given by E= 19+8*sin(pi*t/12)

Find the time(s), correct to the nearest minute, on this day when the temperatures inside and outside the hothouse are equal. 

cheers

So if you algeberise the expression once you make them equal (which is what the question is asking you to do) you get

Solving that on your CAs, you get the first 2 solutions; 2.458 and 9.542. Converting these into hours and minutes you get 2 hours 27 minutes and 9 hours 33 minutes. The first times they will be equal is at 10:27 and then at 5:33.

Hope that helps

[keltingmeith]

In case people didn't notice (lel), nobody in here is answering - this /probably/ due to university coming back. Don't expect to get as many answers now as you have been over the past few months. You might have to seek guidance from other places (e.g., your teacher. Don't be scared about looking stupid in front of them, the question's only dumb if you ask it twice) [there is also the option of other VCE students answering questions - I will always maintain a daily quality control to make sure bad answers are fixed, so don't be scared to try answering something yourself!!]

Hey guys quick question; thanks in advance

The temperature inside a hothouse is controlled so that sensitive plants can survive. The temperature, T degrees C, at time t hours after 8 am is given by the equation
T= 22+3*sin(pi*t/12). On one particular day the temperature outside the house, E degrees C, is given by E= 19+8*sin(pi*t/12)

Find the time(s), correct to the nearest minute, on this day when the temperatures inside and outside the hothouse are equal. 

cheers

We want to know when the outside temperature, E, is the same as the inside temperature, T. So, let E=T, and solve for t.

EDIT: Floatzel provided working, keeping what I have for explanation reasons.

Say if we got this question in an exam and it was worth 2 marks .How would we have to set out our working out?

Find the value of c in the following, correct to 3 decimal places.

Pr(Z ≥ c) = 0.45

, by normalisation. This means that

Popping this into your equation:



By CAS, c=answer.

[knightrider]

In case people didn't notice (lel), nobody in here is answering - this /probably/ due to university coming back. Don't expect to get as many answers now as you have been over the past few months. You might have to seek guidance from other places (e.g., your teacher. Don't be scared about looking stupid in front of them, the question's only dumb if you ask it twice) [there is also the option of other VCE students answering questions - I will always maintain a daily quality control to make sure bad answers are fixed, so don't be scared to try answering something yourself!!]



, by normalisation. This means that

Popping this into your equation:



By CAS, c=answer.

Thanks eulerfan101 

[knightrider]

How would you do this question?

The height of Year 9 students is known to be normally distributed with a mean of 160 cm and a
standard deviation of 8 cm. Answer the following; correct to 2 decimal places.

How tall is Luisa if she is shorter than 80% of Year 9 students?

[Zealous]

How would you do this question?

The height of Year 9 students is known to be normally distributed with a mean of 160 cm and a
standard deviation of 8 cm. Answer the following; correct to 2 decimal places.

How tall is Luisa if she is shorter than 80% of Year 9 students?

If she is shorter than 80% of students, this means she will be taller than 20% of students. Use your inverse normal function on your CAS to calculate the z-score that covers 20% of the standard normal distribution (where the mean is 0 and the standard deviation is 1) you should get z=-0.841.

You can then solve for 'x' using the z-score formula:





You can play around with this site here to visualise it: http://onlinestatbook.com/2/calculators/inverse_normal_dist.html

[pinklemonade]

Could someone please show all steps to find the exact value of the definite integral

I don't know what I'm doing wrong !!!

[cosine]

Could someone please show all steps to find the exact value of the definite integral

I don't know what I'm doing wrong !!!

[knightrider]

If she is shorter than 80% of students, this means she will be taller than 20% of students. Use your inverse normal function on your CAS to calculate the z-score that covers 20% of the standard normal distribution (where the mean is 0 and the standard deviation is 1) you should get z=-0.841.

You can then solve for 'x' using the z-score formula:





You can play around with this site here to visualise it: http://onlinestatbook.com/2/calculators/inverse_normal_dist.html

Thanks so much Zealous 

[garytheasian]

could ii please get an answer to this questions?
i got k = +/- root(-4m), for m<0 but im not sure if im right

[StupidProdigy]

could ii please get an answer to this questions?
i got k = +/- root(-4m), for m<0 but im not sure if im right

that's right