## Reflection: Pacing Sum and Difference Day 1 of 2 - Section 1: Bell Work

I routinely discuss how a calculator give approximate values for irrational numbers. This is good in some cases but in this situation if you are dealing with angles in space or on the earth where you round can make a big difference to position. Scientist will wait until the final calculation to round so they do not accumulate error that can cause major problems.

To make the point I will compare the distance between the terminal side of a 74 degree anlge to a 75 degree angle. If necessary I will get out my smart protractor and draw the angles. You could also use Geogebra for this demonstration.

Calculator approximations
Pacing: Calculator approximations

# Sum and Difference Day 1 of 2

Unit 9: Trigonometric Identities
Lesson 9 of 14

## Big Idea: After analyzing a proof for the sum of angles sine formula, students work to produce the other sum and difference formulas.

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Standards:
Subject(s):
Math, Trigonometric identities, sum and difference formulas
70 minutes

### Katharine Sparks

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