Basically, I am trying to generate a half sine wave using excel. The waveform that I am looking for is a wave which has a positive component from $0$ to $\pi$ and a zero component from $\pi$ to $2\pi$. Image attached for reference (red graph). I'm looking for the equation of said graph. Graph of half-rectified sine wave
[Math] the equation of a half sine wave
trigonometry
Related Solutions
Ok, I have found how to fit my sine curve. I have done it by adding delta y between those two vectors into the value of found sine function (blue). However, the sine wave which is now fitted between points is a little bit different (violet). I got a question for all you experts, does it affect the length of sine wave which i found or the length of the original and "moved" curves are the same? Here is the image
Try the following, where $t$ represents the main parameter, $\theta$ is the tilting angle as the sine wave wraps around the cylinder, $k$ is the frequency of the sine wave, and $a$ is the amplitude:
$$\begin{align*} x(t) &= \cos (t \cos \theta - a \sin \theta \sin (k t)) \\ y(t) &= \sin (t \cos \theta - a \sin \theta \sin (k t)), \\ z(t) &= t \sin \theta + a \cos \theta \sin (k t). \end{align*}$$
Fancy animated picture! 
Best Answer
How about $$ f(x) = \frac{1}{2}\left(\sin(x) + \left| \sin{x} \right| \right) $$