求导计算过程如下：y=lncos1/xy'=(1/cos1/x)*(-sin1/x)*(-1/x^2)=tan(1/x)/x^2.y=√a²-x²y'=(-2x)/2√a^2-x^2=-x/√a^2-x^2y=ln(1+x²)y'=[1/(1+x^2)]*2x=2x/(1+x^2).
