sinarctanx

sinarctanx sin(arctanx)怎样进一步化简啊？求详细步骤……

设tana=x 则：sin(arctanx)=sina sina/cosa=x cosa=sina/x sin²a+cos²a=1 sin²a+sin²a/x²=1 sin²a=x²/(x²+1) sina=±根号[x²/(x²+1)] sin(arctanx)=sina=±根号[x²/(x²+1)]

sinarctanx=?cosarctanx=?tanarcsinx=?tanarcc