1. The problem statement, all variables and given/known data I'm searching for the integral that gives arcosu 2. Relevant equations as we know : ∫u'/[1-u^2]^0.5 dx = arcsinu derivative of arccosu = -u'/[1-u^2]^0.5 + C derivative of arcsinu= u'/[1-u^2]^0.5 3. The attempt at a solution when I type the -u'/[1-u^2]^0.5 on the online integral calculator it always gives me -arcsinu +C Why it doesn't gives arccosu is the arccosu=-arcsinu?! and what is the integral that gives arcosu?