例3求函数p= arctan( (tanha)的导数 解y= (tanh x) 1+ tanha 1 1 1+ tanh" x cosh" x 1+ sinh cosh x 2 cosh x coshx+sinh-x 1+2sinh x 上页例 3 求函数 y = arctan(tanh x)的导数. 解 (tanh ) 1 tanh1 2   +  = x x y x x 2 2 cosh1 1 tanh1  + = x xx 2 22 cosh1 cosh sinh 1 1  + = x x 2 2 cosh sinh 1+ = . 1 2sinh 1 2 + x =