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Please make me understand this simplest function,

y = cos θ

2. in the next step it says: cos θ = sin (π/2 - θ)

3. and similarly -cos (π/2 - θ) = -sin θ.

Can anyone please explain how the steps 2 & 3 are deduced.

Thanks,

Nesta

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

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# Homework Help: Basic trignometry function

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