##### Trigonometry

This is basically a lot of ideas knicked from Resourceaholic. Sorry @mathsjem! Quite happy with this, though. I have used this with my year 9 class this year and I think I’ve taught trig better than I ever have before.

Starts with sine. Talking about similar triangles.

Not using the calculator yet. I want them to appreciate that these are ratios, not just buttons on a calculator!

Then it moves onto two example problem pairs. I introduced the button on the calculator at this point.

Then some questions.

I went through the same process for cosine. I really spent a lot of time talking about just sine and just cosine this year. I think it really helped understanding.

Then, picking between (Don’t worry. The highlights animate in).

Then I introduced tan in the same way.

Some more practice on just tan, very much like the sin practice.

Then a mix of everything.

That was 2.5 lessons. And we didn’t even talk about finding the angle.

Trying to take the time and teach it right first time.

I think there’s possibly more to add here. I think I could have written something about answers or questions when you’re given a ratio like cosx.

Obviously there’s no problem solving AT ALL here.

There’s no mention of SOHCAHTOA. Good.

I think I’m going to write a separate trigonometry problems PowerPoint.