Cosecant Function is Odd
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Theorem
Let $x \in \R$ be a real number.
Let $\csc x$ be the cosecant of $x$.
Then, whenever $\csc x$ is defined:
- $\map \csc {-x} = -\csc x$
That is, the cosecant function is odd.
Proof
\(\ds \map \csc {-x}\) | \(=\) | \(\ds \frac 1 {\map \sin {-x} }\) | Cosecant is Reciprocal of Sine | |||||||||||
\(\ds \) | \(=\) | \(\ds \frac 1 {-\sin x}\) | Sine Function is Odd | |||||||||||
\(\ds \) | \(=\) | \(\ds -\csc x\) | Cosecant is Reciprocal of Sine |
$\blacksquare$
Also see
- Sine Function is Odd
- Cosine Function is Even
- Tangent Function is Odd
- Cotangent Function is Odd
- Secant Function is Even
Sources
- 1968: Murray R. Spiegel: Mathematical Handbook of Formulas and Tables ... (previous) ... (next): $\S 5$: Trigonometric Functions: $5.31$
- 1968: Murray R. Spiegel: Mathematical Handbook of Formulas and Tables ... (previous) ... (next): $\S 5$: Trigonometric Functions: Functions of Angles in All Quadrants in terms of those in Quadrant I