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- Definition: Cosine of a Real Variable
- Definition: Sine of a Real Variable
- Definition: Tangent of a Real Variable
- Proposition: Continuity of Cosine and Sine
- Proposition: Pythagorean Identity
- Proposition: Additivity Theorems of Cosine and Sine
- Proposition: Infinite Series for Cosine and Sine
- Proposition: Special Values for Real Sine, Real Cosine and Complex Exponential Function
- Proposition: Inverse Cosine of a Real Variable
- Proposition: Inverse Sine of a Real Variable
- Proposition: Inverse Tangent of a Real Variable