I'm trying to use inverse cosine, in the cosine rule to find an angle of a triange when you know 3 sides. I know this formula and have it written down. However I've left my calculator and I'm having to use Google:
http://www.google.co.uk/webhp?hl=en#sclient=psy&hl=en&site=webhp&source=hp&q=arccos((5.9%5E2+%2B+4.1%5E2+-+3.2%5E2)+%2F+(2++5.9++4.1))++in+degrees&aq=f&aqi=&aql=&oq=&gs_rfai=&pbx=1&qscrl=1&fp=3dd9e71350957573
but it doesn't return the correct answer which makes think theres a difference between arccos and inverse cos.