Greek Dyslexia

I've spent all morning trying to get a complicated calculation to work. Checked all of the different values twice, did it by hand to see if I'd put something into Excel wrong, no luck. Have eventually realised that I was getting my Greek letters mixed up. g and l look far too similar to me! (that's gamma & lambda - blogger doesn't seem to have symbol font).

Quite annoying, but I'm happy to have found my way to the right answer at last!