求导x^(12)+y^(1
求导：x^(1/2)+y^(1/2)=a^(1/2)(a>=0)求导：x^(1/2)+y^(1/2)=a^(1/2)(a>=0)
arctan(y/x)=ln(x^2+y^2)^(1/2)
(1)x^(1/2)+y^(1/2)=a^(1/2)(a>=0) 1/2*x^(-1/2)+1/2*y^(-1/2)*y'=0 y'=-(y/x)^(1/2) ?硑'=-鏍?y/x)?? (2)arctan(y/x)=ln(x^2+y^2)^1/2 1/[1+(y/x)^2]*(y/x)'=1/2*1/(x^2+y^2)*(x^2+y^2)' (y'x-y)/(x^2+y^2)=(x+yy')/(x^2+y^2) y'x-y=x+yy' y'=(x+y)/(x-y)??
才给五分奖励 也太少了吧 哈哈~~~
答：y' = (1+x²)'/(1+x²) = 2x/(1+x²) y" = [(1+x²)(2x)' - (1+x²)'(2x)/(1+x²)² = 2(1-x²...详情>>
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