Shift question - effective angle

Given a certain shift (let's say 15mm) and a given sensor size (35mm) and a given focal length (say 45mm), how do I compute the exact angle of the left and right corners when doing horizontal shift?

Or same question the other way around, if you assemble a "panorama" taken by shifting left and right, what is the effective angle of the whole shot?

http://lmgtfy.com …view+from+tilt+​shift+lens

Seeing as I'm nice, here is a direct link, Scroll down near the bottom: http://www.cambridgein​colour.com …ls/tilt-shift-lenses1.htm