5.1/5.3 Sum and Difference Formulas for Cos, Sin, and Tan

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Flap 1

Flap 2

cos(α + β) =

cosα cosβ - sinα sinβ

cos(α - β) =

cosα cosβ + sinα sinβ

sin(α + β) =

sinα cosβ + cosα sinβ

sin(α - β) =

sinα cosβ - cosα sinβ

tan(α + β) =

tanα + tanβ / 1- tanα tanβ

tan(α - β)

tanα - tanβ / 1+ tanα tanβ