y=tan(x+y),求dy/dx

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y=tan(x+y),求dy/dx

y=tan(x+y),求dy/dx
y=tan(x+y),求dy/dx

y=tan(x+y),求dy/dx
dy/dx=sec²(x+y)*(1+dy/dx)则[1-sec²(x+y)]dy/dx=sec²(x+y)
则dy/dx=sec²(x+y)/[1-sec²(x+y)]=1/cos²(x+y)÷[1-1/cos²(x+y)]=1/(cos²(x+y)-1)=-1/sin²(x+y)

这是隐函数的求导。
把y看做是x的函数,两边对x求导,得
y'=[sec(x+y)^2]×(1+y')
解上式,得
y'=[sec(x+y)^2]/[1-sec(x+y)^2]
=1/[cos(x+y)^2]/{1-1/[cos(x+y)^2]}
=﹣1/[sin(x+y)^2]
其中,
y'=dy/dx,
cos(x+y)^2=cos(x+y)×cos(x+y)

dy/dx=sec^(x+y)+sec^(x+y)dy/dx dy/dx=sec^(x+y)/1-sec^(x+y)