设y=ln(x+根号(x^2+4),求d^2y/dx^2

一道高数题,设y=ln【f（x）】,其中f’’（x）存在,求(d^2y)/(dx^2) , 设x+y^2+z=ln(x+y^2+z)^1/2,求dz/dx 设参数函数x=ln(1+t^2),y=t-arctant.求(d^2y)/(dx^2). 已知=ln[x+根号(x^2+1)],求二阶导数d^2y/dx^2 设 x/y=ln(y/x) ,求 dy/dx 设｛x=ln√（1+t^2),y=arctant,求 dy/dx及d^2·y/d·x^2 求微分 方程y-2x=(x-y)ln(x-y) 求dy/ dx 和d^2y/ dx^2 设ln(x^2+y^2)=arctan(y/x),则dy/dx= y=ln√1-2x,求dy/dx! 设y=ln(x²+2) ,求y＇ . 设y=ln(x+根号下(x^2+a^2)),求dy. 求隐函数y的二阶导数d^2y/dx^2 siny=ln(x+y)