y=ln [x+√(x^2+4)]
两边取指数:
e^(y)=x+√(x^2+4)
[e^(y)-x]^2 = x^2+4
两边对x求导:
2[e^(y)-x][y'e^(y)-1]=2x
解出:y'e^(y)-1=x/[e^(y)-x]
y' = {1+x/[e^(y)-x]}/e^(y)
y' = {1+x/√(x^2+4)}/[x+√(x^2+4)]
y=ln [x+√(x^2+4)]
两边取指数:
e^(y)=x+√(x^2+4)
[e^(y)-x]^2 = x^2+4
两边对x求导:
2[e^(y)-x][y'e^(y)-1]=2x
解出:y'e^(y)-1=x/[e^(y)-x]
y' = {1+x/[e^(y)-x]}/e^(y)
y' = {1+x/√(x^2+4)}/[x+√(x^2+4)]