Miss Lim's pointers on how to draw graphs

Yesterday, Miss Lim pointed out the following mistakes when we visited her. So here are the following pointers to take note of.

1)Curve rule

• Use the rough part of the curve rule. You will notice there is a smooth edge and a rough edge. Use the rough edge to allow smoother lines.
• When using the curve rule, you form the shape with your flexi curve and use the OUTER part of the flexi curve
• It is advisable to use a combination of curve rule and the french curve. Use the curve rule for drawing the turning point while using the french curve for the other points. This would speed up your plotting.

I know this may sound confusing. We will try to explain to you all during class.

2)Plotting

• Your crosses do not have to be so tiny. Miss Lim says that this may make the marker unable to see the crosses once you have drawn the graph.
• Join the points one at a time. There is NO need to form the curve at one shot. For the maximum point, join three crosses together instead. This would make things less tedious.
• When the table is given, it is not neccesary to draw it again on your graph paper. It will waste time and may also interfere with your curve.
• Do NOT draw the curve at any white portion of the graph paper. You will be penalised for that.

3)Answering

• The line of symmetry must be a full straight line.
• When they ask you to find the value of y when x is a certain value or vice versa, you would have to show on the where the point is by linking it to the y and x axis with dotted lines. Remember to also write the values of y and x at the side of the y and x axis respectively. Also, do not extend your curve or use the equation to find out the values if it is not in the curve. I think we would also have to explain this in class.
• When the graph is given with several points marked out with alphabets like A,B and C. Answer like this C (0,9). Not like this C=(0,9), C is/are (0,9) or C 0,9.

There is also one point to take note for the part where you use linear graphs to find out answer for simulatenous linear equations. The three scenarios are as followed

1. Unit solution. There is one set of solutions for x and y. This means that you can use the point of intersection to find out the answer for the simultaneous linear equations to find out the only set of solutions for x and y in the simultaneous linear equation.
2. No solution. This occurs when the lines are parallel when the gradient is the same and do not intersect. This means that you cant solve the simultaneous linear equations.
3. Infinite solution. This occurs when the equations of both lines are exactly the same, causing them to overlap. This means that there is an infinite number of locations where the lines "intersect" and the number of solutions for x and y is infinity.

Miss Lim says she hopes we will be able to pull through this CA paper. She advises all 2B students to keep practising drawing curves to speed up our drawing time as we are only given 40 minutes for the whole paper.

Chee-yang