令x=y=-1 ∴f(1)=-2f(-1), ∴f(-1)=0 令x=y=0,f(0)=0 令y=-1,f(-x)=-f(x)∴f(x)是奇函数 F(y)=f(x*y/x)=y/xf(x)+xf(y/x)F(y/x)=f(y*1/x)=1/xf(y)+yf(1/x)∴f(y)=y/xf(x)+f(y)+xyf(1/x)令y=x ∴f(x)=f(x)+f(x)+x ²...
d²y/dx²=d/dx(dy/dx)= d/dx(-Fx/Fy)= - [Fxx*1+Fxy*(dy/dx)-Fx(Fyx*1+Fyy*(dy/dx)]/F²y (这里F(x,y)是二元函数,y也是关于x的函数)再将dy/dx = -Fx/Fy带入整理即得答案d²y/dx²=-(FxxF²y-2FxyFxFy+FyyF²x)/F³y ...
xy+yz+zx=1 y＋yfx'+z+xfx'＝0 z对y的偏导 x＋z+yfy'＋xfy' ＝0 z对y的偏导 1+fx'+yfxy"+fy'+xfxy" =0 1+(fx'+fy')+(x+y)fxy"=0 由 得:1+fx'+fy' =1-(y+z)/(x+y)-(x+z)/(x+y) =-2z/(x+y) (x+y)fxy"=2z/(x+y) fxy" =2z/(x+y)^2 ...
推出方程F(x,y)=0所确定的隐函数y的二阶导数公式:d²y/dx²=-(FxxFy2-2FxyFxFy+FxyFx2)/Fy3公式应为:d²y/dx²=-(FxxF²y-2FxyFxFy+FyyF²x)/F³y等号后面的一系列x,y,xx,xy均为下标 下载作业帮APP学习辅导没烦恼 答案解析 结果1 举报 dy/dx = -Fx/Fyd²y/dx²=d/dx(...
=d/dx(dy/dx)= d/dx(-Fx/Fy)= - [Fxx*1+Fxy*(dy/dx)-Fx(Fyx*1+Fyy*(dy/dx)]/F²y （这里F(x,y)是二元函数，y也是关于x的函数）再将dy/dx = -Fx/Fy带入整理即得答案 d²y/dx²=-(FxxF²y-2FxyFxFy+FyyF²x)/F³y ...