㏑(x+根号下(1+x的2次方))'
= 1/(x+根号下(1+x的2次方)) * (x+根号下(1+x的2次方))'
= 1/(x+根号下(1+x的2次方)) * (1+x/根号下(1+x的2次方))
= (1+x/根号下(1+x的2次方))/(x+根号下(1+x的2次方))
= (根号下(1+x的2次方)+x)/(根号下(1+x的2次方)(x+根号下(1+x的2次方)))
= 1/(根号下(1+x的2次方)
㏑(x+根号下(1+x的2次方))'
= 1/(x+根号下(1+x的2次方)) * (x+根号下(1+x的2次方))'
= 1/(x+根号下(1+x的2次方)) * (1+x/根号下(1+x的2次方))
= (1+x/根号下(1+x的2次方))/(x+根号下(1+x的2次方))
= (根号下(1+x的2次方)+x)/(根号下(1+x的2次方)(x+根号下(1+x的2次方)))
= 1/(根号下(1+x的2次方)