GC can be used to check the solution to differential equation.
Example from 2014 P1 Q10
Suppose we want to check whether the following solution to 10 iv is correct:
Enter the following in GC
Since Y2 and Y3 gave the same values, the solution is correct.
Enter the data in the GC as follows:
Variance can also calculated using the GC as follows:
2016 P1 Q7
a) Hence part
Common methods to find the other root are long division or compare coef. A faster method is to use the sum of roots taught in additional maths.
Comments from examiner’s report
Method 1: Change Xres to 3
The Xres button refers to pixel resolution (1 through 8). At Xres = 1, functions are evaluated and graphed at each pixel on the x-axis. At Xres = 8, functions are evaluated and graphed at every eighth pixel along the x-axis. Small Xres values improve graph resolution but may cause the calculator to draw graphs more slowly. Setting Xres to 3 provides good balance between speed and resolution.
Time taken to plot= 23.4 s
Time taken to plot= 3.6 s
Savings of almost 20 seconds! Which is crucial in exams
Method 2: Turn off “Detect Asymptotes”
Suppose we want to check whether our answers for the following is correct:
We can use our GC to check as follows:
Since both expressions give the same values, the answer is correct.
Tips: Write the terms using functions. For bottom rows, write from last row and then write the last 2nd row.
Many students did not consider the number of possible arrangements (permutations) in probability. The following examples illustrate the common error:
Example 1, 2011 P2, Q9
Example 2, CJC Prelim 2016 P2, Q5ii