Nokia Handwriting Calculator has just been updated for S60 5th Edition, with support for scientific functions like sin, cos, tan, ln, etc., although the symbols can't be written directly and have to be dragged from a toolbar at present.  There's also a new help system and support for the math constants ‘e’ and pi - which you can write directly.

Calculate handwritten math expressions

Handwriting Calculator is a showcase of Nokia’s new handwriting recognition technology. It allows you to calculate handwritten math expressions with a touch-screen Nokia device (and with a Windows PC).

Compatibility and system requirements

S60, Maemo, and Windows.

• The S60 version is tested on Nokia 5800 XpressMusic and should work on all Nokia touch devices based on S60 5th Edition.
• The Maemo version is tested on Nokia N800 and N810, and should work on all Nokia internet tablet devices with OS2008 software.
• The PC version is tested on Windows XP SP2 and Vista. It should work on all recent compatible PC with no special requirement on hardware.