They also commented, at the end of the lesson, that it was quieter and that they had done more work than usual. One problem they had was that some pupils were not reading off the values of tan , but were just measuring the length or counting the number of small squares. This was picked up by other pupils and quickly corrected. Tan 90 didn't cause the problems I thought it might. Hence any discussion was fairly short lived.
Pupils get out unit circles etc. drawn for homework.
This lesson we are going to do something slightly different from last lesson. This time we don't have a tangent so we are going to measure our angle and extend the line to the circumference of the circle. So we have a right angled triangle. This length will be called the sine. This length will be called the cosine.