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TrigonometryComments

Trigonometry

sinsin θ = cos ( θ - ½ π )
coscos θ = sin ( θ + ½ π )
Small Angle Approximations

When θ is extremely small, for example if one cathetus is several orders of magnitude than the other, we can use the following approximations:

sin θ ≈ θ
cos θ ≈ 1 - ½ θ2
tan θ ≈ θ