Solving basic trigonometric equations

A complete lesson on solving equations of the form sinx = a, asinx = b and asinx+b=0 (or with cos or tan) in the range 0 to 360 degrees. Designed to come after pupils have spent time looking at the functions of sine, cosine and tangent, so that they are familiar with the symmetry properties of these functions. See my other resources for lessons on these precursors.

I made this to use with my further maths gcse group, but could be used with A-level classes too.

Activities included:

Starter:
A set of four questions, effectively equations but presented as visual graph problems, to remind pupils of the symmetry properties of sine and cosine and the fact that tangent repeats every 180 degrees.

Main:

• An example to transition from a visual problem to a formal, worded problem, and a reminder of the symmetry properties of sine and cosine.
• Five examples of solving trigonometric equations of increasing difficulty, including graphical representations to help pupils understand.
• A set of similar questions for pupils to do independently. I’ve made this into a worksheet where the graphs are included, to scaffold the work. Includes an extension task where pupils create equations with a required number of solutions.

Plenary:
A “spot the mistake” that addresses a few common misconceptions.

Printable worksheets and answers provided.

Please review f you buy as any feedback is appreciated!