TouchCalc Free is a calculator app for Symbian S60 5th mobiles such as Nokia 5800 XpressMusic, X6, N8, C6, N97 and 5530 XpressMusic. Use this form like you would use a regular calculator. Landscape mode is optimized for keyboarded devices, while keyboardless devices should be used in portrait mode.
The last button lets you access the last-used functions; a list of all supported functions can be had via the menu button. Open the Options menu to start graphing.