1. Teaching Ideas for Trigonometry
Yes, that section….

2. Things to tackle in Trigonometry
Pythagoras
Reciprocals
Ratios
Special Angles and proving the CAST diagram
Graphs – the effects of a, p and q
Proving identities

3. Handy things to know COMPETITION!!
Math Drill
Question?25
◄ + ‒ x ÷ + ‒ x ÷ ►
SELECT & [ENTER]
COMPETITION!!
Don’t forget to come past our stand – fastest time wins a SHARP microwave!!
Drill Mode
Press
Answer the questions and press
If you accidently type in something wrong press

4. Class marks Press Type in what you are converting to, e.g. 100
×55=
68 3 4
Press
Type in what you are converting to, e.g. 100
Type in what you are converting from, e.g. 80
Type in first student’s mark
Then simply type in the next student’s mark and again

5. PRIME FACTORIZATION!!!!!! Press
96 =
25x3
Press
Type in the number you want to prime factorize.
Tada!! 

6. Pythagoras Type in the x-coordinate Pressθ:
Type in the x-coordinate
Press
Then type in the y-coordinate

7. You can also go backwards…
5,36.87 →xy X: Y:
Type in hypotenuse
Press
Type in angle

8. Reciprocals
1 cos 30 =
For sec x:
Press
For cosec x:
For cot x:

9. Ratios Save sin-1 into D1 key: Now press and 1 2 STORING D1
SELECT FUNCTION
Save sin-1 into D1 key:
Now press and

10. Special Angles
Or use your calculator: 30
And so on…

11. Proving the CAST Diagram.
X_Start:
-90.
X_Step:
15_
Press
Start with sin – so type in
At X-Start, start at -90 so type in
At X-Step, type in 15

12. Look at the y-values between
X ANS
Look at the y-values between
-90 and 0
0 and 90
90 and 180
180 and 270
270 and 360
360 and 450
450 and 540 and so on…

13. Now let’s do cos Press Now type in
X ANS
Press
Now type in
At X-Start, start at -90 again, so press
At X-Step, leave as 15, so

14. And now tan Press Now type in At X-Start, start at -90 again, so press
X ANS
Press
Now type in
At X-Start, start at -90 again, so press
At X-Step, leave as 15, so

15. So what have we got? Notice a pattern? Tan(x) Tan(x) Cos(x) Cos(x)
Sin(x)
Sin(x)
Tan(x)
Cos(x)
Sin(x)
Cos(x)
Sin(x)
Sin(x)
Sin(x)
Tan(x)
Tan(x)
Cos(x)
Tan(x)

16. Lets look at the positives:90 S A
0 or 360
180 T C
270

17. Graphs – the effects of a, p and q:
Basic Sin graph:
As we did when proving the CAST diagram – plot the coordinates.

18. Let’s investigate a: Press 2 x 3 Plot the new coordinates.
What happens if
a = ½?

19. Yes, it gets smaller:

20. Same idea for p = 1, 2, and ½

21. And q = 0, +1, -1

22. Proving Identities Prove that sin 2 𝑥 + cos 2 𝑥 =1 Press
(sinX)2 + (cosX)2_
Prove that sin 2 𝑥 + cos 2 𝑥 =1
Press

23. Thank you! Take a look at www.mathsatsharp.co.za
for lots of high school worksheets with memos, sample exam
papers and resources for Maths and Mathematical Literacy.