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Mrs Tibble’s Year 11207 comments to Mrs Tibble’s Year 11 |
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As I said above: come after school on Monday. This is your own fault, Hannah. If you had brought your book to the lesson, it would have been marked with all the others.
Trig answers can be checked by putting them back into the calculator – read my last message to Katie.
hi miss
sorry this is late but i was at an open evening
i cant do the last question(perimeter one) im using the area formula like you said but i get a math error when i do sin-1(13.44- which was my answer for the formula bit so im a bit stuck??
Katie
Hi Katie,
Use area = 0.5 ab sinC
and put the numbers in the right place!
Tidy up the right hand side
then sinC = area/ans
then inverse sine it to get the angle.
Katie, it’s the last step you’ve got wrong:
You know the area (given in question) so 13.44 x sin B = 10
how do i change the mode on my calculator :O
ahh i can’t do it without my calculator !!! please help mrs T
wooo i did it!!!! don’t worry!
oh wait… it is now on degree mode and science mode HELP PLEASE
Hi Idil,
Degree mode is fine!
Press SHIFT MODE 2 to hopefully restore normality!!
Have fun
no no it comes out weird
for instance:
5^2 = 2.5 x10^01
That’s not ‘weird’ – it’s called standard form lol.
Did you press SHIFT, MODE/SETUP, 2 (the one that says lineIO)
PS Errr …….. why are trying to do 5-squared on a calculator?
okay panic over THANKS
Good. Enjoy the paper
hi mrs.tibble
could i have some help of question 3 b) of the recent paper… x and y are different prime numbers
(i) Write down the HCF of the two expressions
x(squared)y xy(squared)
(ii)
write down the LCM of the twp expressions
x(squared)y xy(squared)
thank you
The HCF of two numbers is the biggest number that’s in both factor lists. As x and y are both prime, they only have factors of 1 and themselves. So the HCF of any two primes x and y is always 1.
Now, if we look at x^2y and xy^2, we know that the HCF is simply going to be the common factor xy – as this is the biggest thing that’s common to both.
You can apply the same sort of logic to LCM… See how you get on with that.
hi miss tibble
on the last page of the homework it says pages and questions from opur textbook but i cant find the questions on the pages??
Katie
Hi Katie,
You should have been given a message to ignore the back page!
JT
miss, u know when you’re doing translation vectors, say you had read off the numbers 3 off the x axis and 7 off the y axis does that mean in the brackets you’d put the 3 on the top?
Hi Charlie,
If you are reading values off the axes, you are finding coordinates not vectors. A translation describes how it has moved, not it’s actual position. It is always the movement in the x-direction first in the bracket.
JT
hey miss im not sure what to do for 1.c of the homework?
Katie
Don’t worry about it Katie: we’ll discuss it in the lesson.
hey miss
im stuck on 2 b. to calculate the setimate mean which values do i add up? and the same for 4b what values am i meant to use? the time or height or freq. density?
Thanks
Kaite
Hi Katie,
Estimated mean = grand total of estimated values / total frequency
For each partial total do middle value of class interval x its frequency.
Add them all up and divide the answer by the sum of all the frequencies.
JT
miss i dont understand what estimated values and partial total is? is class interval the x axis on the graph?
Katie
Hi Katie,
The class interval is the width of the group in your grouped data, so it’s the width of the bar read off the scale on the x axis. Because you don’t have all the data, you can’t do an exact mean value so you assume all the values are in the middle of the class interval. In the train times question we did in class, the 1st bar went from 0-5, so the mid-value would be 2.5. Multiply that by the frequency of that bar (area NOT height) and that will give you the contribution to the grand total from that particular bar. Do this with all the bars and add up your answers.
Then add up all your frequencies to find out how many pieces of data there are.
Divide 1st answer by 2nd to get estimated mean.
oh ok got it thank you
and for median what am i putting in order? is it the waiting time on the x axis-smallest to largest?
Katie
Hi Katie, the data is already plotted in order. Once you know how many pieces of data there were (the sum of the frequencies), then work out which one is in the middle of the list and then work out which bar it is hiding in!
my answer like goes off the chart, it doesnt go in any of the bars because my sum of frequencies is 61
Katie
Katie,
It’s 61 for Q4 but not Q2.
hey miss…..how was your Christmas?
i need help, i don’t understand loci :/
HELP!!!!
Hi Hannah,
What’s the problem? Is it just the word? Replace ‘locus’ with ‘path’ to help you understand what you are being asked.
eg the locus of all points 3cm from point X is the path made by all the points which are 3cm from X so it will be a circle of radius 3cm around X.
Does that help? Read the rule and think that all the points on your line have to obey that rule.
Have fun.
JT
hi miss,
im abit baffelled on how to go about answering question 24 on the calculator paper?
hi miss,
im abit baffelled on how to go about answering question 24 on the calculator paper?
is it pythagoras or triganometry or neither coz its not a right angled triangle?!
Hi Charlie,
You can only use Pythagoras and SOH CAH TOA in right-angled triangles. In other triangles you need the Cosine Rule and/or the Sine Rule (on formula sheet)
JT
Rite, thankyou miss!
hello. i still don’t understand how to do question 24 from what you said to charlie above!
i have done question 20 and my internet has been down until just this moment, which was annoying…
Also i just found the piece of paper that fell out of my other maths paper with my answers on! which was even more annoying, i will bring it tomorrow
Thanks
Hi Idil,
You can calculate the area of the triangle using 1/2 ab sinC (all the angles are 60 as it’s equilateral)
The sector has radius 3cm so you can work out its area.
Subtract to find the shaded area.
JT
hi miss not sure how to work this so i assume this will get to you thanx
Hi Niamh,
You’re through OK now. Feel free to post any questions here.
JT
Hi Miss,
on the last question on the pink sheet, with method would to calculate the bearing of D from A?
Hi Sam,
I don’t have the question here and can’t remember what the diagram looks like!
If you want the bearing of D from A, then you’re AT A and going TO D. So, from A, face North and turn clockwise till you face D. Mark that angle on the paper.
Is it an angle you can calculate as part of a triangle? Can you work it out knowing other angles?
Sorry, that might not be very helpful until I see the question. We have a lesson tomorrow.
JT
hey mrs tibble
i am really confused about the whole of question 12 on the greeny coloured paper.
Q12!!!
You’re ahead of me Hannah lol!
What do we call line DC?
What do we call line BC?
There’s a theorem about the angle between these two lines. That will get you (a)(i)
Angle DBC is on a straight line with the angle inside the triangle. That will give you the next one.
(b) similar triangles have the same set of angles.
(c) props of similar triangles – everything is in the same ratio (scale factor)
oh and mrs tibble i forgot to remind you to have extra lessons during my prep!
my prep lesson is 4th period, are you free then?
That’s when I’ve arranged to see Lucy. If you only need a couple of things sorted, you can come along then, but if you want longer, we’ll need to book up another time. When are your frees?
i dont mind so long as i am going over maths really
both my frees are on fridays but in week b its 4th period and on week a its 2nd period.
Come along at the start of period 4 then, but make sure the teacher who sits with you knows.
mrs, im abit baffelled bout how to do number 7 in the homework… coz both x and y have positive and negative values….
Hi Charlie,
That doesn’t matter. Just make sure you take note of those signs when adding or subtracting.
JT