Tuesday, 7 October 2014

Concluding Year 2014...

Dear S1-04

It has been a pleasure to be with you on your maiden learning journey in SST :) 
The closure of this academic year would a good time for us to reflect and plan for the following year.

We would like to hear your experience as the feedback would be taken into account when we shape your learning experience, as well as your juniors'.

Click HERE to access the Feedback Form.



Saturday, 27 September 2014

2-to-3 Quiz (Revision) Construction

Question 1

To construct the figure:
(i) Measure and draw line AB using ruler.

(ii) Measure and draw angle ABC using protractor.

(iii) Stretch the 2 arms of the compass to measure 5.2 cm and mark an arc on the line BC. Label it point C.

Here are 2 ways of drawing the parallel line DC
(iv) Use a protractor to draw angle BCD
OR
(iv) Use a set-square and ruler to draw line CD

(v) Stretch the 2 arms of the compass to measure 3.8 cm, place the sharp end at "C" and mark an arc on the line DC. Label it point D.

(vi) Join A and D to complete the figure.



Question 2

Three properties to take note of:

  • Diagonals of the rhombus bisect each other
  • Diagonals of the rhombus are perpendicular to each other
  • Opposite angles are equal




Algebra - More Practice

Dear S1-04

Please refer to the additional Algebra handout that was given to you on Wednesday (24 Sep).
Click HERE to view suggested solution


[Someone asked...] The difference between Approximation and Estimation...

Estimation involves calculation, whereas Approximation is about rounding off a number.
  • The rounding off of a number can be carried out before or after the calculation.

Consider the following scenario:
The length of the door is 1.95 m and its height is 2.06 m (assuming that the dimensions given are exact).

(a) Find the area of the door and round the answer off to 2 significant figures.
The actual area of the door is 1.95 m x 2.06 m = 4.017 m^2.
Answer = 4.0 m^2 (to 2 sig fig) [Ans]

The step to round off a number (to present the final answer) is an approximation.
There is no mention of estimation in question (a), so we use the given values to compute the area first, then round off as required.

(b) Estimate the area of the door to 2 significant figures.

The purpose of doing 'estimate' or 'estimation' is to enable us carry out calculation quickly and when we don't need an exact value. A rough figure should give us a sense of the actual value. It should not be too far off from the actual value. 

To estimate, we will round the numbers off to the required "degree of accuracy" (in this case, 2 significant figures) first before doing any calculation. In other words, we are using the approximated numbers to do calculation.

Area of the door ≈ 2.0 m x 2.0 m <<<<< This is the 'estimation' step when the approximated values are used for calculation
= 4.0 m^2 [Ans]

Since 1.95 m ≈ 2.0 m (2 sig fig) and  2.06 m ≈ 2.0 (2 sig fig)


Exception
When doing Estimation, we round off the values based on the degree of accuracy given.

However, there is an exception when dealing with roots because by rounding it off to 1 SF, 2 SF, etc. may not land itself nicely to be rooted.

To estimate square root of 26.77, it does not help us to figure out what number it's 'near' to if we round it off to 1 SF (i.e. 30) or 2 SF (i.e. 27). 
However, we know that 25 (which is a perfect square) is quite close to it; so, we will estimate it to be square root of 25, and get the answer "5". 
If you key square root 26.77 in the calculator, your answer should be quite close to 5.


To extend/ combine the above.... 
If the question asks: Estimate 150.5677 x "square root of 8.343" to 2 sig fig
Then we'll have 150.5677 x "square root of 8.343" ≈ 150 x "square root 9" 
= 150 x 3
= 450 [Ans]

150.5677 when rounded off to 2 sig fig = 150
square root of 8.343 will be square root of 9 (which is the closest perfect square).

Tuesday, 23 September 2014

Revision (2-to-3 Quiz): Linear Graph Question 1 - It should be...

Answers

(a) Recall, on the graph paper, each 'big' square with the 'darkened' green link measures 2 cm x 2 cm.

(b) Substitute the given values of x and y to find the unknowns.

(c) Remember to check the domain for the plot.




(d) Things that must be present when plotting the graph:

  • label x and y axes
  • markings on the axes must be clearly indicated/ written (including the origin)
  • label the line with the given equation
  • plot the points with crosses clearly

 


(e) To read points, the working is represented by the dotted lines.




Revision (2-to-3 Quiz): Linear Graph Question 1

Refer to Handout 2-to-3 Quiz (10) Question 1
For discussion...