Lesson 28 Graph of the rotating arm
Lesson plan
Piagetian Level | ||
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3 B Mature Formal |
![]() ‘you are asking us to extend the idea of ‘sine’ outside the context of triangles, and into rotations in general’ |
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‘between O°and 20° and 160°and 180° the graph becomes a straight line: as the arm approaches 90° it’s got no further to go’ | ||
3A Early Formal |
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‘angles that have sine = 0.7 are both 45° and 135° — then to get sine 1000° you have to imagine the curves repeating themselves fo the right’ |
‘sine of -10° is the same as sine 350°' | ||
2B* Concrete Generalisation |
![]() Interpreting angle as a measure of turn in relation fo sine ratio |
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2B Mature concrete |
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Mid concrete |
Episode 1 Sine ratios in 1st two quadrants |
Episode 2 Sines beyond 180° |