## Reflection: Complex Tasks Trigonometric Identities - Day 1 of 2 - Section 2: Explore

Deriving the even function identity (cos(-x) = cosx) was pretty straightforward to students because of the symmetry of the graph to the y-axis. Discussing the odd function identity was more challenging for students.

Here is a diagram of what we came up with together during our discussion. Students understood that the sine of -x would equal the sine of -y, but they had a difficult time expressing this relationship as an identity. In the image are the two possibilities that students came up with and they were able to critique the reasoning of others to reach a consensus that sin(-x) = -sin(x).

# Trigonometric Identities - Day 1 of 2

Unit 5: Trigonometric Relationships
Lesson 1 of 15

## Big Idea: Identifying what makes a trig expression complex will keep you focused on what needs to be simplified.

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40 minutes

### Tim Marley

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