FOR GMS ICSE 2014 23rd Aug

Dear Students, today we commence study of Ch 9 : REFLECTION

For the study of this chapter, you would need to use graph paper.
Kindly remember that drawing graphs is a work of art and neatness is the key.

• pencils should be sharpened well before drawing.
• do NOT use a rubber
• follow the following conventions :
• the X-axis and Y-axis are continuous lines and should be drawn with arrow heads at the ends of the lines.
• all writing on the graph must be IN PENCIL ONLY - do not use a pan at all.
• marking of numbers on the graphs should be below the X-axis and to the left of Y-axis
• look at the sum you are about to do and then decide by looking at the greatest value of the abscissa  and the greatest value of the ordinates and then decide on the length of the axis and the scale to be used. Generally use no less than 1cm = 1 unit.

 You have most probably studied 'Reflection' in Physics. However, our general understanding of reflection tells us that when an image is reflected it will be at the same distance behind the mirror / water as the object is in front of it.

In our study we will work at reflection in the X-axis (the line y = 0 - because the value of the ordinate on all points on this line will be 0); Y-axis (the line x = 0 - because the value of the abscissa on all points on this line will be 0) and through the Origin O (0,0) - the point of intersection of the X-axis and Y-axis.

Please look at pgs.117 / 118 : 9.5, 9.6 and 9.7 and the diagrams will show you what happens when a point is reflected in the X-axis, Y-axis and the Origin, respectively.

Note that if a point A is reflected, its reflection will be denoted as A'

Please note that a point remains unchanged under reflection in the following cases :

• when a point is reflected in the axis on which it lies
• when the origin (0,0) is reflected in the Origin, the X-axis and in the Y-axis

Now let's go to Ex 9 (A). Let's do sum nos 3, 4, 5, 6, and 7 first. Let us also do them graphically (i.e.draw the points and their reflection on a graph).

How will you do these sums ?

1. look at the points you have to reflect - name them A, B and C.
2. check the value of the abscissa and ordinates and see what length you will need to draw the X-axis and Y-axis e.g. in No.3 the values of the  abscissa are from -5 to + 3 - so you will draw the X-axis from -6 to +4. Since the values of the ordinates are from 0 to 4, you will draw the Y-axis from +5 to -5. Why to -5 in the Y-axis? because since the points are reflected in the X-axis the values of the ordinates in the reflect points will be the opposite of the ordinates in the original points.
3. plot point A. plot its reflection - what will its ordinates be ? The coordinates of the reflected point will be (3, -2)
4. Now do the same with the other sums
5. Check you answers (after you have tried, please !)

All the best !

Class XI Sc & Com Eng Drama 22nd - 23rd Aug

Dear Students,

Please make sure that you have worked up to page 37 in our Play Arms and the Man.

When we return to class on the 24th we shall be continuing from that part of the play !

Do well !

FOR GMS ICSE 2014 22nd Aug

Ex.Today, we need to draw our attention to :

Ex.12 (C) Nos. 4, 16, 18, 21, 29 and Ex.12 (D) : Nos 1, 2, 3, 7, 9, 10, 14, 17, 18

In all these sums we are trying to find the value of unknown elements : x, y, a, b, c and so forth.

Various mathematical operations have been used : addition, subtraction, multiplication and division.

Points to remember :

• a NULL or ZERO matrix is a matrix in which all elements in the matrix are 0
• an IDENTITY is a matrix is a SQUARE matrix in which all the elements excelpt the elements in the primary diagonal are 0
• In multiplication first note the order of each matrix before you need to multiply and note the order of the resultant matrix
• If you are doing the following matrix A - 2B, multiply the matrix B by 2 (i.e. each element of the matrix will be multiplied by 2) and then subtract the result from matrix A. Do not multiply each element in matrix B by -2 !

Ex.12 (C) : 17, 25,  Ex.12 (D) : 4, 6

In these sums you need to find the value of an unknown Matrix M

Points to remember :

• e.g.in Ex.12 (C) 17 (i) : 
• First we need to ask : in what order will the matrix M be if when it is multiplied with a matrix with an order 2 x 2, results in a matrix with an order 1 x 2 ? The answer is that the order of matrix M will be 1 x 2 - why ? because the resultant matrix [1  2] takes the row of the first matrix and the columns of the second matrix.
• Since M is a matrix of the order 1 x 2, then we can let it be [x   y] 
• now you proceed in multiplying matrix M and the 2 x  matrix
• then proceed to find the values of x and y as you did in the sums above.

Ex.12 (C) : 30, Ex.12 (D) : 5, 20

In these sums we find that we need to fill in the trignometircal values for certain numbers.

Before doing the sums we need to revise the values of sin, cos and tan for 0, 30, 45, 60 and 90 degrees. then you carry on !

You have quite a few sums to do today ! However, in the three types of sums, there's just a slight change in the type. The main work is practice - especially when multiplying matrices. One needs to be careful !

Remember, if you have any difficulty, I am only an e-mail away !

XI Sc Eng Drama 21st to the 23rd Aug

Good day !

Today (21st), Tomorrow (22nd) and the day after tomorrow (23rd) , I want you to go back to the beginning of the test.

• Practice reading ! Now that you are familiar with the text - read it with expression ! This will help you appreciate and understand the characters better ! 
• Make notes on the side of any new insight you get into the characters or the themes of the plot of the play ! Remember that your ideas are what count ! 

All the best !

FOR GMS ICSE 2014 21st August

Good day !

If you have been keeping up with the work I have been posting, we can now move onto Ex.12 (C) : 30, Ex 12 (D) 5, 20

These would require to you to first of all revise your sin, cos and tan values of 0, 30, 45, 60 and 90 degrees.

Once you do that these sums should give you no problem ! But work them out !

All the best !

FOR GMS ICSE 2014 20th Aug

Dear students,

I am working with the 12 boarders and Aniket here.

Those of you who have yet to go through the posts in Maths I have on this blog kindly do so - I shall be starting with multiplication today with the lads here - and the.n we shall continue together - so keep practising.

Just check if you have done Ex.12 (C) nos. 8, 9, 10, 11, 12, 14, 15, 22, 23, 24, 25, 26, 27, 28

XI Sc Eng Drama 20th Aug

Dear Students,

Today I want you to catch up with the work I have done via this blog - as when I met some of you last week you seemed not to have followed it daily ! Please do the needful.

I shall be moving head from tomorrow !

All the best !