Difference between revisions of "Sine"

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(Properties)
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The sine function, usually written $\sin$, is the solution of the second order initial value problem $y''=-y;y(0)=0$.
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The sine function $\sin \colon \mathbb{R} \rightarrow \mathbb{R}$ is the unique solution of the second order initial value problem $y''=-y;y(0)=0,y'(0)=1$.
  
 
=Properties=
 
=Properties=

Revision as of 20:32, 2 October 2014

The sine function $\sin \colon \mathbb{R} \rightarrow \mathbb{R}$ is the unique solution of the second order initial value problem $y=-y;y(0)=0,y'(0)=1$.

Properties

Proposition: $\sin(x)=\displaystyle\sum_{k=0}^{\infty} \dfrac{(-1)^kx^{2k+1}}{(2k+1)!}$

Proof: proof goes here █

Proposition: $\sin(x) = x \displaystyle\prod_{k=1}^{\infty} \left( 1 - \dfrac{x^2}{k^2\pi^2} \right)$

Proof: proof goes here █