In 9.x, you need to surround most operators (including "/") with white space, Lynn. A good approach is to first carry out a complex series of calculations one at a time in the Raster Calculator so you can catch such problems right where they happen. Later you can combine them into a monolithic expression for SOMA.BTW, it's simpler (and more accurate) to square the sine rather than subtract the square of the cosine from 1: remember, 1 - cos^2(x) = sin^2(x).