text: y=(1-x^2)^(1/2)\n\nhere ,we use the substitution\nx=sinp,then dx=cospdp\n1-x^2=1-sin^2(p)=cos^2(p)\ncosp=(1-x^2)^(1/2)\n\nint(1-x^2)^(1/2)dp\n=int(cosp*cosp)^(1/2)dp\n{plugging in substitution}\n=1/2int(1+cos2p)dp\n{trig identity}\n=1/2(p+1/2sin2p) \n=1/2(p+sinp*cosp)\n{trig identity}\nbut,cosp=(1-x^2)^(1/2),\np=sin^-1(x)\n{above}\n=1/2sin^-1(x)\n+1/2x*(1-x^2)^(1/2)\n=1/2{arcsinx+x*(1-x^2)^(1/2)}\n+C\n\nwhere C is an arbitrary constant\n\nif there is anything you don't\nfollow,give me a call-this is\nan important substitution\n\ni hope that this helps