Tips to A Math TYS questions

p. 112 Q16a

Find the x coordinate of the point on the line y= 5 - 2x where xy is a maximum.

How to think in this question?
Firstly, we usually do dy/dx and we need to have a y function in terms of x e.g. y=ax+bx^4.
In this question, there is no direct function of x. However, you are given y= 5 - 2x and xy. Can you put them together?

i.e. substitute y= 5 - 2x into xy?
Then you differentiate the function w.r.t x.
To find max or min, the 1st derivative =0.

p. 110 Q11
Some of you asked me what is a flower bed?
In this IT age, you can utilize the wonderful internet and just GOOGLE it!

Jay Chou sang about a chrysanthemum flower bed -- 菊花台
You can also see the link here for FLOWER BED

The important thing here is to sketch a simple diagram based on the requirements of the question.

And the diagram is VERY simple! Only a circle and a square!
However, there may be different ways to draw them.

No matter how you lay these two flower beds, your fence will be the perimeters of these two shapes. Hence, x(x) + circumference of circle = 40 (total lengthof fence as given by the question). You can then express x in terms of r and pi.