How to plot helicoid in Runiter a graphing calculator 3D application from windows store?

[Win_odd Dhamnekar]

Hello,
I want to know how to plot the helicoid in graphing calculator 3D application from windows store? I know \(\theta= \arctan{(\frac{y}{x})}\) and \(z=\rho*\cos{(\phi)}\)

 

[Dr.Peterson]

Where are you having difficulty? I would use cylindrical coordinates, not spherical as you seem to be suggesting.

 

[Win_odd Dhamnekar]

I got the helicoid graph in the graphing calculator 3D using cylindrical co-ordinates